Measuring transducer of vibration-type, as well as an in-line measuring device having such a measuring transducer

ABSTRACT

A measuring transducer serves for registering at least one physical, measured variable of a flowable medium guided in a pipeline and/or for producing Coriolis forces serving for registering a mass flow rate of a flowable medium guided in a pipeline. The measuring transducer comprises: a transducer housing; four, straight, measuring tubes connected to flow dividers for guiding flowing medium along flow paths. Each of the four measuring tubes opens with an inlet-side, measuring tube end into one the flow openings of an inlet-side, flow divider and with an outlet-side, measuring tube end into one of the flow openings. An electromechanical exciter mechanism for producing and/or maintaining mechanical oscillations of the four measuring tubes. The exciter mechanism is embodied in such a manner, that, the measuring tubes are excitable pairwise to execute opposite phase bending oscillations in, in each case, a shared imaginary plane of oscillation. The measuring transducer is suitable, especially, for measuring a density and/or a mass flow rate of a medium flowing in a pipeline, at least at times, with a mass flow rate of more than 2200 t/h.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Nonprovisional application, which claims thebenefit of U.S. Provisional Application No. 61/202,543, filed on Mar.11, 2009, and also U.S. Provisional Application 61/213,742, filed onJul. 9, 2009.

TECHNICAL FIELD

The invention relates to a measuring transducer of vibration-type formeasuring a medium flowably guided in a pipeline, especially a gas,liquid, powder or other flowable material, especially for measuring adensity and/or a mass flow rate, especially also a mass flow integratedover a time interval, of a medium flowing in a pipeline, at least attimes, with a mass flow rate of more than 2200 t/h, especially more than2500 t/h. Additionally, the invention relates to an in-line measuringdevice having such a measuring transducer.

BACKGROUND DISCUSSION

Often used in process measurements, and automation, technology formeasuring physical parameters, such as e.g. the mass flow, the densityand/or the viscosity, of media flowing in pipelines are in-linemeasuring devices, which, by means of a measuring transducer ofvibration-type, through which medium flows, and a measuring, andoperating, circuit connected thereto, effect, in the medium, reactionforces, such as e.g. Coriolis forces corresponding with mass flow,inertial forces corresponding with density of the medium and/orfrictional forces corresponding with viscosity of the medium, etc., andproduce derived from these a measurement signal representing theparticular mass flow, viscosity and/or density of the medium. Suchmeasuring transducers, especially measuring transducers embodied asCoriolis, mass flow meters or Coriolis, mass flow/densimeters, aredescribed at length and in detail e.g. in EP-A 1 001 254, EP-A 553 939,U.S. Pat. No. 4,793,191, US-A 2002/0157479, US-A 2006/0150750, US-A2007/0151368, U.S. Pat. No. 5,370,002, U.S. Pat. No. 5,796,011, U.S.Pat. No. 6,308,580, U.S. Pat. No. 6,415,668, U.S. Pat. No. 6,711,958,U.S. Pat. No. 6,920,798, U.S. Pat. No. 7,134,347, U.S. Pat. No.7,392,709, or WO-A 03/027616.

Each of the measuring transducers includes a transducer housing, ofwhich an inlet-side, first housing end is formed at least partially bymeans of a first flow divider having exactly two, mutually spaced,circularly cylindrical, or tapered or conical, flow openings and anoutlet-side, second housing end is formed at least partially by means ofa second flow divider having exactly two, mutually spaced, flowopenings. In the case of some of the measuring transducers illustratedin U.S. Pat. No. 5,796,011, U.S. Pat. No. 7,350,421, or US-A2007/0151368, the transducer housing comprises a rather thick walled,circularly cylindrical, tubular segment, which forms at least a middlesegment of the transducer housing.

For guiding the medium, which flows, at least at times, the measuringtransducers include, furthermore, in each case, exactly two measuringtubes of metal, especially steel or titanium, which are connected suchthat the medium can flow in parallel and which are positioned within thetransducer housing and held oscillatably therein by means of theaforementioned flow dividers. A first of the, most often, equallyconstructed and, relative to one another, parallel extending, measuringtubes opens with an inlet-side, first, measuring tube end into a firstflow opening of the inlet-side, first flow divider and with anoutlet-side, second measuring tube end into a first flow opening of theoutlet-side, second flow divider and a second of the measuring tubesopens with an inlet-side, first measuring tube end into a second flowopening of the first flow divider and with an outlet-side, secondmeasuring tube end into a second flow opening of the second flowdivider. Each of the flow dividers includes additionally, in each case,a flange with a sealing surface for fluid tight connecting of themeasuring transducer to tubular segments of the pipeline serving,respectively, for supplying and removing medium to and from themeasuring transducer.

For producing the above discussed reaction forces, the measuring tubesare caused to vibrate during operation, driven by an exciter mechanismserving for producing, or maintaining, as the case may be, mechanicaloscillations, especially bending oscillations, of the measuring tubes inthe so-called wanted mode. The oscillations in the wanted mode are, mostoften, especially in the case of application of the measuring transduceras a Coriolis, mass flow meter and/or densimeter, developed, at leastpartially, as lateral bending oscillations and, in the case of mediumflowing through the measuring tubes, as a result of therein inducedCoriolis forces, as additional, equal frequency oscillationssuperimposed in the so-called Coriolis mode. Accordingly, the—here mostoften electrodynamic—exciter mechanism is, in the case of straightmeasuring tubes, embodied in such a manner, that, therewith, the twomeasuring tubes are excitable in the wanted mode, at least partially,especially also predominantly, to opposite phase bending oscillations ina shared plane of oscillation, differentially—thus through introductionof exciter forces acting simultaneously along a shared line of action,however, in opposed direction.

For registering vibrations, especially bending oscillations, of themeasuring tubes excited by means of the exciter mechanism and forproducing oscillation measurement signals representing vibrations, themeasuring transducers have, additionally, in each case, a, most often,likewise electrodynamic, sensor arrangement reacting to relativemovements of the measuring tubes. Typically, the sensor arrangement isformed by means of an inlet-side, oscillation sensor registeringoscillations of the measuring tubes differentially—thus only relativemovements of the measuring tubes—as well as by means of an outlet-side,oscillation sensor registering oscillations of the measuring tubesdifferentially. Each of the oscillation sensors, which are usuallyconstructed equally with one another, is formed by means of a permanentmagnet held on the first measuring tube and a cylindrical coil held onthe second measuring tube and permeated by the magnetic field of thepermanent magnet.

In operation, the above described inner part of the measuringtransducer, formed by means of the two measuring tubes as well as thethereon held exciter mechanism and sensor arrangement, is excited bymeans of the electromechanical exciter mechanism, at least at times, toexecute mechanical oscillations in the wanted mode at least onedominating, wanted, oscillation frequency. Selected as oscillationfrequency for the oscillations in the wanted mode is, in such case,usually a natural, instantaneous, resonance frequency of the inner part,which, in turn, depends essentially both on size, shape and material ofthe measuring tubes as well as also on an instantaneous density of themedium; in given cases, this wanted oscillation frequency can also beinfluenced significantly by an instantaneous viscosity of the medium. Asa result of fluctuating density of the medium being measured and/or as aresult of media change occurring during operation, the wantedoscillation frequency during operation of the measuring transducervaries naturally, at least within a calibrated and, thus, predetermined,wanted frequency band, which correspondingly has a predetermined lower,and a predetermined upper, limit frequency.

For defining a free, oscillatory length of the measuring tubes and,associated therewith, for adjusting the band of the wanted frequency,measuring transducers of the above described type include, additionally,most often, at least one inlet-side, coupling element, which is affixedto both measuring tubes and spaced from the two flow dividers, forforming inlet-side, oscillation nodes for opposite phase vibrations,especially bending oscillations, of both measuring tubes, as well as atleast one outlet-side, coupling element, which is affixed to bothmeasuring tubes and spaced both from the two flow dividers, as well asalso from the inlet-side, coupling element, for forming outlet-side,oscillation nodes for opposite phase vibrations, especially bendingoscillations, of the measuring tubes. In the case of straight measuringtubes, in such case, a minimum separation between inlet side and outletside coupling elements (which, thus, belong to the inner part)corresponds to the free, oscillatory length of the measuring tubes. Bymeans of the coupling elements, additionally also an oscillation qualityfactor of the inner part, as well as also the sensitivity of themeasuring transducer, in total, can be influenced, in a manner suchthat, for a minimum required sensitivity of the measuring transducer, atleast one minimum, free, oscillatory length is provided.

Development in the field of measuring transducers of vibration-type has,in the meantime, reached a level, wherein modern measuring transducersof the described type can, for a broad application spectrum of flowmeasurement technology, satisfy highest requirements as regardsprecision and reproducibility of the measurement results. Thus, suchmeasuring transducers are, in practice, applied for mass flow rates fromsome few l/h (gram per hour) up to some t/min (tons per minute), atpressures of up to 100 bar for liquids or even over 300 bar for gases.The accuracy of measurement achieved, in such case, lies usually atabout 99.9% of the actual value, or above, or at a measuring error ofabout 0.1%, wherein a lower limit of the guaranteed measurement rangecan lie quite easily at about 1% of the measurement range end value. Dueto the high bandwidth of their opportunities for use, industrial grademeasuring transducers of vibration-type are available with nominaldiameters (corresponding to the caliber of the pipeline to be connectedto the measuring transducer, or to the caliber of the measuringtransducer measured at the connecting flange), which lie in a nominaldiameter range between 1 mm and 250 mm and at maximum nominal mass flowrate of 2200 t/h, in each case, for pressure losses of less than 1 bar.A caliber of the measuring tubes lies, in such case, for instance, in arange between 80 mm and 100 mm.

In spite of the fact that, in the meantime, measuring transducers foruse in pipelines with very high mass flow rates and, associatedtherewith, very large calibers of far beyond 100 mm have becomeavailable, there is still considerable interest in obtaining measuringtransducers of high precision and low pressure loss also for yet largerpipeline calibers, about 300 mm or more, or mass flow rates of 2500 t/hor more, for instance for applications in the petrochemical industry orin the field of transport and transfer of petroleum, natural gas, fuels,etc. This leads, in the case of correspondingly scaled enlarging of thealready established measuring transducer designs known from the state ofthe art, especially from EP-A 1 001 254, EP-A 553 939, U.S. Pat. No.4,793,191, US-A 2002/0157479, US-A 2007/0151368, U.S. Pat. No.5,370,002, U.S. Pat. No. 5,796,011, U.S. Pat. No. 6,308,580, U.S. Pat.No. 6,711,958, U.S. Pat. No. 7,134,347, U.S. Pat. No. 7,350,421, or WO-A03/027616, to the fact that the geometric dimensions would beexorbitantly large, especially the installed length corresponding to adistance between the sealing surfaces of both flanges and, in the caseof curved measuring tubes, a maximum lateral extension of the measuringtransducer, especially dimensions for the desired oscillationcharacteristics, the required load bearing ability, as well as themaximum allowed pressure loss. Along with that, also the empty mass ofthe measuring transducer increases unavoidably, with conventionalmeasuring transducers of large nominal diameter already having an emptymass of about 400 kg. Investigations, which have been carried out formeasuring transducers with two bent measuring tubes, constructed, forinstance, according to U.S. Pat. No. 7,350,421 or U.S. Pat. No.5,796,011, as regards their to-scale enlargement to still greaternominal diameters, have, for example, shown that, for nominal diametersof more than 300 mm, the empty mass of a to-scale enlarged, conventionalmeasuring transducer would lie far above 500 kg, accompanied by aninstalled length of more than 3000 mm and a maximum lateral extension ofmore than 1000 mm. As a result, it can be said that industrial grade,mass producible, measuring transducers of conventional design andmaterials with nominal diameters far above 300 mm cannot be expected inthe foreseeable future both for reasons of technical implementability,as well as also due to economic considerations.

SUMMARY OF THE INVENTION

Proceeding from the above recounted state of the art, it is consequentlyan object of the invention to provide a measuring transducer of highsensitivity and high oscillation quality factor, which also in the caseof large mass flow rates of more than 2200 t/h, causes only a smallpressure loss of less than 1 bar and which also has a construction,which is as compact as possible at large nominal diameters of over 250mm.

For achieving the object, the invention resides in a measuringtransducer of vibration-type for registering at least one physical,measured variable of a flowable medium guided in a pipeline, especiallya gas, a liquid, a powder or other flowable material, and/or forproducing Coriolis forces serving for registering a mass flow rate of aflowable medium guided in a pipeline, especially a gas, a liquid, apowder or other flowable material. The measuring transducer comprises,according to the invention, a, for example, essentially tubular and/orexternally circularly cylindrical, transducer housing, of which aninlet-side, first housing end is formed by means of an inlet-side, firstflow divider having exactly four, for example, circularly cylindrical,tapered or conical, flow openings spaced, in each case, from oneanother, and an outlet-side, second housing end is formed by means of anoutlet-side, second flow divider having exactly four, for example,circularly cylindrical, tapered or conical, flow openings spaced, ineach case, from one another. Furthermore, the measuring transduceraccording to the invention comprises exactly four, straight measuringtubes forming flow paths arranged for parallel flow and connected tothe, for example, equally constructed, flow dividers for guiding flowingmedium, especially, measuring tubes held oscillatably in the transducerhousing only by means of said flow dividers and/or equally constructedand/or at least pairwise parallel relative to one another. Of the fourmeasuring tubes of the measuring transducer of the invention, a firstmeasuring tube, especially a circularly cylindrical, first measuringtube, opens with an inlet-side, first measuring tube end into a firstflow opening of the first flow divider and with an outlet-side, secondmeasuring tube end into a first flow opening of the second flow divider,a second measuring tube, especially a circularly cylindrical, secondmeasuring tube, opens with an inlet-side, first measuring tube end intoa second flow opening of the first flow divider and with an outlet-side,second measuring tube end into a second flow opening of the second flowdivider, a third measuring tube, especially a circularly cylindrical,third measuring tube, opens with an inlet-side, first measuring tube endinto a third flow opening of the first flow divider and with anoutlet-side, second measuring tube end into a third flow opening of thesecond flow divider, and a fourth measuring tube, especially acircularly cylindrical, fourth measuring tube, opens with an inlet-side,first measuring tube end into a fourth flow opening of the first flowdivider and with an outlet-side, second measuring tube end into a fourthflow opening of the second flow divider. Additionally, the measuringtransducer of the invention comprises an electromechanical excitermechanism, for example, one formed by means of an electrodynamicoscillation exciter, for producing and/or maintaining mechanicaloscillations, for example, bending oscillations, of the four measuringtubes, wherein the exciter mechanism is embodied in such a manner that,therewith, the first measuring tube and the second measuring tube areexcitable, during operation, to opposite phase, bending oscillations ina shared, imaginary, first plane of oscillation, and the third measuringtube and the fourth measuring tube are excitable, during operation, toopposite phase, bending oscillations in a shared, imaginary, secondplane of oscillation, especially a second plane of oscillationessentially parallel to the first plane of oscillation.

In a first further development of the invention, the measuringtransducer additionally comprises a first coupling element of firsttype, especially a plate-shaped first coupling element of first type,which is affixed at least to the first measuring tube and to the secondmeasuring tube and spaced on the inlet side both from the first flowdivider as well as also from the second flow divider for forminginlet-side, oscillation nodes at least for vibrations, especiallybending oscillations, of the first measuring tube and for theretoopposite phase vibrations, especially bending oscillations, of thesecond measuring tube, as well as a second coupling element of firsttype, especially a plate-shaped second coupling element of first typeand/or a second coupling element constructed equally to the firstcoupling element and/or a second coupling element parallel to the firstcoupling element, which second coupling element of first type is affixedat least to the first measuring tube and to the second measuring tubeand spaced on the outlet side both from the first flow divider as wellas also from the second flow divider, as well as also from the firstcoupling element, for forming outlet-side, oscillation nodes at leastfor vibrations, especially bending oscillations, of the first measuringtube and for thereto opposite phase vibrations, especially bendingoscillations, of the second measuring tube.

In a first embodiment of the first further development of the invention,it is additionally provided, that all four measuring tubes are connectedwith one another mechanically by means of the first coupling element offirst type as well as by means of the second coupling element of firsttype.

In a second embodiment of the first further development of theinvention, it is additionally provided, that the first coupling elementof first type is plate shaped, especially in such a manner, that it hasessentially a rectangular, square, round, cross shaped or H-shaped basicshape.

In a third embodiment of the first further development of the invention,it is additionally provided, that the second coupling element of firsttype, especially a coupling element of construction equal to that of thefirst coupling element of first type, is plate shaped, especially insuch a manner, that it has a rectangular, square, round, cross shaped orH-shaped basic shape.

In a fourth embodiment of the first further development of theinvention, it is additionally provided, that the first coupling elementof first type is affixed also to the third measuring tube and to thefourth measuring tube, and that the second coupling element of firsttype is affixed to the third measuring tube and to the fourth measuringtube.

In a fifth embodiment of the first further development of the invention,it is additionally provided, that a center of mass of the first couplingelement of first type has a distance to a center of mass of themeasuring transducer, which is essentially equal to a distance of acenter of mass of the second coupling element of first type to saidcenter of mass of the measuring transducer.

In a sixth embodiment of the first further development of the invention,the measuring transducer is additionally so embodied, that a free,oscillatory length, L_(18x), of the first measuring tube, especially ofeach of the measuring tubes, corresponding to a minimum separationbetween the first coupling element of first type and the second couplingelement of first type, amounts to less than 2500 mm, especially lessthan 2000 mm and/or more than 800 mm. Especially, the measuringtransducer is, in such case, additionally so embodied, that each of thefour measuring tubes, especially measuring tubes of equal caliber and/orequal length, has a caliber, which amounts to more than 60 mm,especially more than 80 mm, especially in such a manner, that a caliberto oscillatory length ratio of the measuring transducer, as defined by aratio of the caliber of the first measuring tube to the free,oscillatory length of the first measuring tube, amounts to more than0.07, especially more than 0.09 and/or less than 0.15.

In supplementation of the first further development of the invention, itis additionally provided, that the measuring transducer furthercomprises a third coupling element of first type, for example, aplate-shaped, third coupling element of first type, which is affixed atleast to the third measuring tube and to the fourth measuring tube andspaced on the inlet side both from the first flow divider as well asalso from the second flow divider, for forming inlet-side, oscillationnodes at least for vibrations, especially bending oscillations, of thethird measuring tube and for thereto opposite phase vibrations,especially bending oscillations, of the fourth measuring tube, as wellas a fourth coupling element of first type, for example, a plate-shaped,fourth coupling element of first type, which is affixed at least to thethird measuring tube and to the fourth measuring tube and spaced on theoutlet side both from the first flow divider as well as also from thesecond flow divider, as well as also from the third coupling element offirst type, for forming outlet-side, oscillation nodes at least forvibrations, especially bending oscillations, of the third measuring tubeand for thereto opposite phase vibrations, especially bendingoscillations, of the fourth measuring tube. In such case, for example,also all four measuring tubes can be connected with one anothermechanically by means of the third coupling element of first type aswell as by means of the fourth coupling element of first type.

In a second further development of the invention, the measuringtransducer additionally comprises a first coupling element of secondtype, for example, a plate shaped or rod shaped, first coupling elementof second type, which is affixed to the first measuring tube and to thethird measuring tube, but otherwise to no others of the measuring tubes,and which is spaced both from the first coupling element of first typeas well as also from the second coupling element of first type forsynchronizing vibrations, especially bending oscillations, of the firstmeasuring tube and thereto equal frequency vibrations, especiallybending oscillations, of the third measuring tube, as well as a secondcoupling element of second type, for example, a plate shaped or rodshaped, second coupling element of second type, which is affixed to thesecond measuring tube and to the fourth measuring tube, but otherwise tono others of the measuring tubes, and which is spaced both from thefirst coupling element of first type as well as also from the secondcoupling element of first type, as well as also from the first couplingelement of second type, especially in such a manner, that the first andsecond coupling elements of second type are placed in the measuringtransducer lying opposite one another, for synchronizing vibrations,especially bending oscillations, of the second measuring tube andthereto equal frequency vibrations, especially bending oscillations, ofthe fourth measuring tube. In supplementation thereof, the measuringtransducer can further comprise a third coupling element of second type,for example, a plate shaped or rod shaped, third coupling element ofsecond type, which is affixed to the first measuring tube and to thethird measuring tube, but otherwise to no others of the measuring tubes,and which is spaced from the first coupling element of second type, forsynchronizing vibrations, especially bending oscillations, of the firstmeasuring tube and thereto equal frequency vibrations, especiallybending oscillations, of the third measuring tube, as well as a fourthcoupling element of second type, for example, a plate shaped or rodshaped, fourth coupling element of second type, which is affixed to thesecond measuring tube and to the fourth measuring tube, but otherwise tono others of the measuring tubes, and which is spaced, in each case,from the second and third coupling elements of second type, especiallyin such a manner, that the third and fourth coupling elements of secondtype are placed lying opposite one another in the measuring transducer,for synchronizing vibrations, especially bending oscillations, of thesecond measuring tube and thereto equal frequency vibrations, especiallybending oscillations, of the fourth measuring tube.

Moreover, the measuring transducer can comprise, additionally, a fifthcoupling element of second type, for example, a plate shaped or rodshaped, fifth coupling element of second type, which is affixed to thefirst measuring tube and to the third measuring tube, but otherwise tono others of the measuring tubes, and which is spaced from the first andthird coupling elements of second type, for synchronizing vibrations,especially bending oscillations, of the first measuring tube and theretoequal frequency vibrations, especially bending oscillations, of thethird measuring tube, as well as a, for example, a plate shaped or rodshaped, sixth coupling element of second type, which is affixed to thesecond measuring tube and to the fourth measuring tube, but otherwise tono others of the measuring tubes, and which is spaced, in each case,from the second, fourth and fifth coupling elements of second type,especially in such a manner that the fifth and sixth coupling elementsof second type are placed in the measuring transducer lying opposite oneanother, for synchronizing vibrations, especially bending oscillations,of the second measuring tube and thereto equal frequency vibrations,especially bending oscillations, of the fourth measuring tube.

In a first embodiment of the invention, it is additionally provided,that each of the four measuring tubes, especially measuring tubes ofequal caliber and/or equal length, has a caliber, which amounts to morethan 60 mm, especially more than 80 mm.

In a second embodiment of the invention, it is additionally provided,that the first flow divider has a flange, especially a flange havingmass of more than 50 kg, for connecting the measuring transducer to atubular segment of the pipeline serving for supplying medium to themeasuring transducer and the second flow divider has a flange,especially a flange having a mass of more than 50 kg, for connecting themeasuring transducer to a segment of the pipeline serving for removingmedium from the measuring transducer. Developing this embodiment of theinvention further, each of the flanges has a sealing surface for fluidtight connecting of the measuring transducer with the, in each case,corresponding tubular segment of the pipeline, wherein a distancebetween the sealing surfaces of both flanges defines an installed lengthof the measuring transducer, especially an installed length amounting tomore than 1200 mm and/or less than 3000 mm. Especially, the measuringtransducer is additionally so embodied, that, in such case, a measuringtube length of the first measuring tube corresponding to a minimumseparation between the first flow opening of the first flow divider andthe first flow opening of the second flow divider is so selected, that ameasuring tube length to installed length ratio of the measuringtransducer, as defined by a ratio of the measuring tube length of thefirst measuring tube to the installed length of the measuringtransducer, amounts to more than 0.7, especially more than 0.8 and/orless than 0.95, and/or that a caliber to installed length ratio of themeasuring transducer, as defined by a ratio of the caliber of the firstmeasuring tube to the installed length of the measuring transducer,amounts to more than 0.02, especially more than 0.05 and/or less than0.09. Alternatively thereto or in supplementation thereof, the measuringtransducer is so embodied, that a nominal diameter to installed lengthratio of the measuring transducer, as defined by a ratio of the nominaldiameter of the measuring transducer to the installed length of themeasuring transducer, is smaller than 0.3, especially smaller than 0.2and/or greater than 0.1, wherein the nominal diameter corresponds to acaliber of the pipeline, in whose course the measuring transducer is tobe used.

In a third embodiment of the invention, it is additionally provided,that a measuring tube length of the first measuring tube correspondingto a minimum separation between the first flow opening of the first flowdivider and the first flow opening of the second flow divider amounts tomore than 1000 mm, especially more than 1200 mm and/or less than 2000mm.

In a fourth embodiment of the invention, it is additionally provided,that each of the four measuring tubes, especially four measuring tubesof equal caliber, is so arranged, that a smallest lateral separation ofeach of the four measuring tubes, especially measuring tubes of equallength, from a housing side wall of the transducer housing is, in eachcase, greater than zero, especially greater than 3 mm and/or greaterthan twice a respective tube wall thickness; and/or that a smallestlateral separation between two neighboring measuring tubes amounts to,in each case, greater than 3 mm and/or greater than the sum of theirrespective tube wall thicknesses.

In a fifth embodiment of the invention, it is additionally provided,that each of the flow openings is so arranged, that a smallest lateralseparation of each of the flow openings from a housing side wall of thetransducer housing amounts, in each case, to greater than zero,especially greater than 3 mm and/or greater than twice a smallest tubewall thickness of the measuring tubes; and/or that a smallest lateralseparation between the flow openings amounts to greater than 3 mm and/orgreater than twice a smallest tube wall thickness of the measuringtubes.

In a third further development of the invention, the measuringtransducer additionally comprises a plurality of annular stiffeningelements, especially equally constructed stiffening elements, servingfor increasing the oscillation quality factor of the measuring tubes.Each of the stiffening elements is so placed on exactly one of themeasuring tubes that it grips around such along one of the peripherallines of the measuring tube. According to an embodiment of the thirdfurther development of the invention, there are placed on each of themeasuring tubes at least four annular stiffening elements, for example,equally constructed stiffening elements, especially in such a manner,that the stiffening elements are so placed in the measuring transducer,that two adjoining stiffening elements mounted on the same measuringtube have, relative to one another, a separation, which amounts to atleast 70% of a tube outer diameter of said measuring tube, at most,however, 150% of such tube outer diameter, for example, a separation inthe range of 80% to 120% of such tube outer diameter.

In a fourth further development of the invention, the measuringtransducer additionally comprises a sensor arrangement for producingoscillation measurement signals representing vibrations, especiallybending oscillations, of the measuring tubes, by reacting to vibrationsof the measuring tubes, especially bending oscillations excited by meansof the exciter mechanism. The sensor arrangement is, for example, anelectrodynamic sensor arrangement and/or is formed by means ofoscillation sensors constructed equally to one another.

In a first embodiment of the fourth further development of theinvention, it is provided, that the sensor arrangement is formed bymeans of an inlet-side, first oscillation sensor, especially anelectrodynamic, first oscillation sensor and/or a first oscillationsensor differentially registering oscillations of the first measuringtube relative to the second measuring tube, as well as by means of anoutlet-side, second oscillation sensor, especially an electrodynamic,second oscillation sensor and/or a second oscillation sensordifferentially registering oscillations of the first measuring tuberelative to the second measuring tube, especially in such a manner thata measuring length of the measuring transducer corresponding to aminimum separation between the first oscillation sensor and the secondoscillation sensor amounts to more than 500 mm, especially more than 600mm and/or less than 1200 mm, and/or in such a manner that a caliber tomeasuring length ratio of the measuring transducer, as defined by aratio of a caliber of the first measuring tube to the measuring lengthof the measuring transducer, amounts to more than 0.05, especially morethan 0.09. Additionally, the first oscillation sensor can be formed bymeans of a permanent magnet held on the first measuring tube and acylindrical coil permeated by the magnetic field of the permanent magnetand held on the second measuring tube, and the second oscillation sensorby means of a permanent magnet held on the first measuring tube and acylindrical coil permeated by the magnetic field of the permanent magnetand held on the second measuring tube.

In a second embodiment of the fourth further development of theinvention, it is additionally provided, that the sensor arrangement isformed by means of an inlet-side, first oscillation sensor, especiallyan electrodynamic, first oscillation sensor and/or a first oscillationsensor differentially registering oscillations of the first measuringtube relative to the second measuring tube, by an outlet-side, secondoscillation sensor, especially an electrodynamic, second oscillationsensor and/or a second oscillation sensor differentially registeringoscillations of the first measuring tube relative to the secondmeasuring tube, by an inlet-side, third oscillation sensor, especiallyan electrodynamic, third oscillation sensor and/or a third oscillationsensor differentially registering oscillations of the third measuringtube relative to the fourth measuring tube, as well as by anoutlet-side, fourth oscillation sensor, especially an electrodynamic,fourth oscillation sensor and/or a fourth oscillation sensordifferentially registering oscillations of the third measuring tuberelative to the fourth measuring tube, especially in such a manner, thata measuring length of the measuring transducer corresponding to aminimum separation between the first oscillation sensor and the secondoscillation sensor amounts to more than 500 mm, especially more than 600mm and/or less than 1200 mm, and/or in such a manner that a caliber tomeasuring length ratio of the measuring transducer, as defined by aratio of a caliber of the first measuring tube to the measuring lengthof the measuring transducer, amounts to more than 0.05, especially morethan 0.09. In such case, in advantageous manner, the first and thirdoscillation sensors can be interconnected electrically in series in sucha manner, that a combined oscillation measurement signal representscombined inlet-side oscillations of the first and third measuring tubesrelative to the second and fourth measuring tube, and/or the second andfourth oscillation sensors can be interconnected electrically in seriesin such a manner, that a combined oscillation measurement signalrepresents combined outlet-side oscillations of the first and thirdmeasuring tubes relative to the second and fourth measuring tube.Alternatively or in supplementation, the first oscillation sensor canfurther be formed by means of a permanent magnet held on the firstmeasuring tube and a cylindrical coil permeated by the magnetic field ofthe permanent magnet and held on the second measuring tube, and thesecond oscillation sensor by means of a permanent magnet held on thefirst measuring tube and a cylindrical coil permeated by the magneticfield of the permanent magnet and held on the second measuring tube,and/or the third oscillation sensor by means of a permanent magnet heldon the third measuring tube and a cylindrical coil permeated by themagnetic field of the permanent magnet and held on the fourth measuringtube and the fourth oscillation sensor by means of a permanent magnetheld on the third measuring tube and a cylindrical coil permeated by themagnetic field of the permanent magnet and held on the fourth measuringtube.

In a sixth embodiment of the invention, it is additionally provided,that a mass ratio of an empty mass of the total measuring transducer toan empty mass of the first measuring tube is greater than 10, especiallygreater than 15 and smaller than 25.

In a seventh embodiment of the invention, it is additionally provided,that an empty mass, M₁₈, of the first measuring tube, especially each ofthe measuring tubes, is greater than 20 kg, especially greater than 30kg and/or smaller than 50 kg.

According to an eighth embodiment of the invention, it is additionallyprovided, that an empty mass of the measuring transducer is greater than200 kg, especially greater than 300 kg.

In a ninth embodiment of the invention, it is additionally provided,that a nominal diameter of the measuring transducer, which correspondsto a caliber of the pipeline, in whose course the measuring transduceris to be used, amounts to more than 100 mm, especially greater than 300mm. In advantageous manner, the measuring transducer is additionally soembodied, that a mass to nominal diameter ratio of the measuringtransducer, as defined by a ratio of the empty mass of the measuringtransducer to the nominal diameter of the measuring transducer, issmaller than 2 kg/mm, especially smaller than 1 kg/mm and/or greaterthan 0.5 kg/mm.

In a tenth embodiment of the invention, it is additionally provided,that the first and the second measuring tubes are of equal construction,at least as regards a material, of which their tube walls are, in eachcase, composed, and/or as regards their geometrical tube dimensions,especially a tube length, a tube wall thickness, a tube outer diameterand/or a caliber.

According to an eleventh embodiment of the invention, it is additionallyprovided, that the third and fourth measuring tubes are of equalconstruction, at least as regards a material, of which their tube wallsare, in each case, composed, and/or as regards their geometric tubedimensions, especially a tube length, a tube wall thickness, a tubeouter diameter and/or a caliber.

In a twelfth embodiment of the invention, it is additionally provided,that the four measuring tubes are of equal construction, as regards amaterial, of which their tube walls are composed, and/or as regardstheir geometric tube dimensions, especially a tube length, a tube wallthickness, a tube outer diameter and/or a caliber. It can, however, alsobe of advantage, when, alternatively thereto, both the third measuringtube as well as also the fourth measuring tube are different from thefirst measuring tube and from the second measuring tube as regards theirrespective geometric tube dimensions, especially a tube length, a tubewall thickness, a tube outer diameter and/or a caliber.

In a thirteenth embodiment of the invention, it is additionallyprovided, that a material, of which the tube walls of the four measuringtubes are at least partially composed, is titanium and/or zirconiumand/or duplex steel and/or super duplex steel.

In a fourteenth embodiment of the invention, it is additionallyprovided, that the transducer housing, the flow dividers and tube wallsof the measuring tubes are, in each case, composed of steel, forexample, stainless steel.

In a fifteenth embodiment of the invention, it is additionally provided,that the minimum bending oscillation, resonance frequencies at least ofthe first and second measuring tubes are essentially equal and theminimum bending oscillation, resonance frequencies at least of the thirdand fourth measuring tubes are essentially equal. In such case, theminimum bending oscillation, resonance frequencies of all four measuringtubes can be essentially equal or, however, also kept only pairwiseequal.

In a sixteenth embodiment of the invention, it is additionally provided,that the four flow openings of the first flow divider are so arranged,that imaginary areal centers of gravity associated with the crosssectional areas, especially circularly shaped cross sectional areas, ofthe flow openings of the first flow divider form the vertices of animaginary square, wherein such cross sectional areas lie in a shared,imaginary cutting plane of the first flow divider extendingperpendicularly to a longitudinal axis of the measuring transducer,especially a longitudinal axis parallel to a principal flow axis of themeasuring transducer.

In a seventeenth embodiment of the invention, it is additionallyprovided, that the four flow openings of the second flow divider are soarranged, that imaginary areal centers of gravity associated with thecross sectional areas, especially circularly shaped cross sectionalareas, of the flow openings of the second flow divider form the verticesof an imaginary square, wherein such cross sectional areas lie in ashared, imaginary cutting plane of the second flow divider extendingperpendicularly to a longitudinal axis of the measuring transducer,especially a longitudinal axis parallel to a principal flow axis of themeasuring transducer.

According to an eighteenth embodiment of the invention, it isadditionally provided, that the exciter mechanism is formed by means ofa first oscillation exciter, especially an electrodynamic, firstoscillation exciter and/or a first oscillation exciter differentiallyexciting oscillations of the first measuring tube relative to the secondmeasuring tube.

Especially, the exciter mechanism, according to a first furtherdevelopment of the eighteenth embodiment of the invention, is formed bymeans of a second oscillation exciter, for example, an electrodynamicsecond oscillation exciter and/or a second oscillation exciterdifferentially exciting oscillations of the third measuring tuberelative to the fourth measuring tube. In such case, it is additionallyprovided, that the first and second oscillation exciters areinterconnected electrically in series, in such a manner, that a combineddriver signal excites combined oscillations of the first and thirdmeasuring tubes relative to the second and fourth measuring tube. Theoscillation exciter of the exciter mechanism can be formed, for example,by means of a permanent magnet held on the first measuring tube and acylindrical coil permeated by the magnetic field of the permanent magnetand held on the second measuring tube, and wherein the secondoscillation exciter is formed by means of a permanent magnet held on thethird measuring tube and a cylindrical coil permeated by the magneticfield of the permanent magnet and held on the fourth measuring tube.

In a second further development of the eighteenth embodiment of theinvention, the measuring transducer further comprises: A first plateshaped stiffening element, which is affixed to the first measuring tubeand to the third measuring tubes, and, indeed, affixed to segments ofthe first and third measuring tubes lying, respectively, between thefirst oscillation exciter and the first flow divider, for tuningresonance frequencies of bending oscillations of the first measuringtube and the third measuring tube in a third plane of oscillationessentially perpendicular to the first and/or second planes ofoscillation; a second plate shaped stiffening element, which is affixedto the second measuring tube and to the fourth measuring tubes, and,indeed, affixed to segments of the second and fourth measuring tubeslying, respectively, between the first oscillation exciter and the firstflow divider, for tuning resonance frequencies of bending oscillationsof the second measuring tube and the fourth measuring tube in a fourthplane of oscillation essentially perpendicular to the first and/orsecond planes of oscillation; a third plate-shaped stiffening element,which is affixed to the first measuring tube and to the third measuringtube, and, indeed, affixed to segments of the first and third measuringtubes lying, respectively, between the first oscillation exciter and thesecond flow divider, for tuning resonance frequencies of bendingoscillations of the first measuring tube and the third measuring tubesin the third plane of oscillation; as well as a fourth plate-shapedstiffening element, which is affixed to the second measuring tube and tothe fourth measuring tubes, and, indeed, affixed to segments of thesecond and fourth measuring tubes lying, respectively, between the firstoscillation exciter and the second flow divider, for tuning resonancefrequencies of bending oscillations of the second measuring tube and thefourth measuring tube in the fourth plane of oscillation.

The plate shaped stiffening elements can, for the case in which thesensor arrangement is formed by means of an inlet-side, firstoscillation sensor and by means of an outlet-side, second oscillationsensor, be arranged in the measuring transducer e.g. in such a mannerthat the first plate shaped stiffening element is affixed to the segmentof the first measuring tube between the first oscillation sensor and thefirst flow divider along one of the straight lateral surface elements ofthe segment, for instance that nearest the third measuring tube, as wellas to the segment of the third measuring tube lying between the firstoscillation sensor and the first flow divider along one of the straightlateral surface elements of the segment, for instance that nearest thefirst measuring tube, the second plate shaped stiffening element isaffixed to the segment of the second measuring tube lying between thefirst oscillation sensor and the first flow divider along one of thestraight lateral surface elements of the segment, for instance thatnearest the fourth measuring tube, as well as to the segment of thefourth measuring tube lying between the first oscillation sensor and thefirst flow divider along one of the straight lateral surface elements ofthe segment, for instance that nearest the second measuring tube, thethird plate shaped stiffening element is affixed to the segment of thefirst measuring tube lying between the second oscillation sensor and thesecond flow divider along one of the straight lateral surface elementsof the segment, for instance that nearest the third measuring tube, aswell as to the segment of the third measuring tube lying between thesecond oscillation sensor and the second flow divider along one of thestraight lateral surface elements of the segment, for instance thatnearest the first measuring tube, and the fourth plate shaped stiffeningelement is affixed to the segment of the second measuring tube lyingbetween the second oscillation sensor and the second flow divider alongone of the straight lateral surface elements of the segment, forinstance that nearest the fourth measuring tube, as well as to thesegment of the fourth measuring tube lying between the secondoscillation sensor and the second flow divider along one of the straightlateral surface elements of the segment, for instance that nearest thesecond measuring tube. Additionally, it is provided in such case thateach of the four plate shaped stiffening elements, for instance plateshaped stiffening elements of equal construction to one another, is, ineach case, so embodied and so placed in the measuring transducer that ithas a height corresponding to a smallest distance between the lateralsurface elements of each two measuring tubes along which it is, in eachcase, fixed, especially a height which is smaller by more than half thana length of said plate shaped stiffening element measured in thedirection of said lateral surface elements. In supplementation thereto,each of the four plate shaped stiffening elements can further, in eachcase, be so embodied that the length of each of the plate shapedstiffening elements is greater, especially two times greater, than abreadth of said plate shaped stiffening element.

In a nineteenth embodiment of the invention, it is additionallyprovided, that a middle segment of the transducer housing is formed bymeans of a straight tube, for example, a circularly cylindrical,straight tube.

In a twentieth embodiment of the invention, it is additionally provided,that the transducer housing is essentially tubularly embodied, forexample, circularly cylindrically embodied. In such case, it isadditionally provided, that the transducer housing has a largest housinginner diameter, which is greater than 150 mm, especially greater than250 mm, especially in such a manner, that a housing to measuring tubeinner diameter ratio of the measuring transducer, as defined by a ratioof the largest housing inner diameter to a caliber of the firstmeasuring tube is kept greater than 3, especially greater than 4 and/orsmaller than 5, and/or that a housing inner diameter to nominal diameterratio of the measuring transducer, as defined by a ratio of the largesthousing inner diameter to the nominal diameter of the measuringtransducer is smaller than 1.5, especially smaller than 1.2 and/orgreater than 0.9, wherein the nominal diameter corresponds to a caliberof the pipeline, in whose course the measuring transducer is to be used.The housing inner diameter to nominal diameter ratio of the measuringtransducer can, in such case, in advantageous manner, be, for example,also equal to one.

Moreover, the invention resides in an in-line measuring device formeasuring a density and/or a mass flow rate, especially also a totalmass flow totaled over a time interval, of a medium, especially of agas, a liquid, a powder or other flowable material flowing in apipeline, at least at times, especially with a mass flow rate of morethan 2200 t/h, which in-line measuring device, especially an in-linemeasuring device embodied as a compact device, comprises one of theaforementioned measuring transducers as well as a measuring deviceelectronics electrically coupled with the measuring transducer,especially also a measuring device electronics mechanically rigidlyconnected with the measuring transducer.

A basic idea of the invention is to use, instead of the two measuringtubes, through which the medium flows in parallel, as used in the caseof conventional measuring transducers of large nominal diameter, fourstraight measuring tubes, through which the medium flows in parallel,and so, on the one hand, to enable an optimal exploitation of thelimited offering of space, while, on the other hand, being able toassure an acceptable pressure loss over a broad measuring range,especially also in the case of very high, mass flow rates of far over2200 t/h. Moreover, the effective flow cross section of the inner partresulting from the total cross section of the four measuring tubes can,in comparison to conventional measuring transducers of equal nominaldiameter and equal empty mass having only two measuring tubes, bedirectly increased by more than 20%.

An advantage of the measuring transducer of the invention residesadditionally in the fact that predominantly established, structuraldesigns, such as regards materials used, joining technology,manufacturing steps, etc., can be applied, or must only be slightlymodified, whereby also manufacturing costs are, in total, quitecomparable to those of conventional measuring transducers. As a result,a further advantage of the invention is to be found in the fact that,thereby, not only an opportunity is created for implementingcomparatively compact measuring transducers of vibration-type also withlarge nominal diameters of over 150 mm, especially with a nominaldiameter of larger 250 mm, with manageable geometric dimensions andempty dimensions, but, additionally, also, this can be accomplished inan economically sensible manner.

The measuring transducer of the invention is, consequently, especiallysuitable for measuring flowable media guided in a pipeline having acaliber of larger 150 mm, especially of 300 mm or greater. Additionally,the measuring transducer is also suitable for measuring also mass flows,which are, at least at times, greater than 2200 t/h, especially, atleast at times, amounting to more than 2400 t/h, such as can occur e.g.in the case of applications for measuring petroleum, natural gas orother petrochemical materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, as well as other advantageous embodiments thereof, willnow be explained in greater detail on the basis of examples ofembodiments presented in the figures of the drawing. Equal parts areprovided in the figures with equal reference characters; when requiredto avoid clutter or when it otherwise appears sensible, alreadymentioned reference characters are omitted in subsequent figures. Otheradvantageous embodiments or further developments, especially alsocombinations of first only individually explained aspects of theinvention, will become evident additionally from the figures of thedrawing.

In particular, the figures of the drawing show as follows:

FIGS. 1 and 2 an in-line measuring device serving, for example, as aCoriolis flow/density/viscosity transducer, in perspective, alsopartially sectioned, side views;

FIGS. 3 a and 3 b a projection of the in-line measuring device of FIG. 1in two different side views;

FIG. 4 in perspective, side view, a measuring transducer ofvibration-type, installed in an in-line measuring device of FIG. 1;

FIGS. 5 a and 5 b a projection of the measuring transducer of FIG. 4 intwo different side views;

FIGS. 6 a and 6 b projections of an inner part of the measuringtransducer of FIG. 4 in two different side views;

FIG. 7 in perspective, side view, a further development of the measuringtransducer of FIG. 4, installed in an in-line measuring device of FIG.1; and

FIGS. 8 a and 8 b a projection of the measuring transducer of FIG. 7 intwo different side views.

DETAILED DISCUSSION IN CONJUNCTION WITH THE DRAWINGS

FIGS. 1, 2 show, schematically, an in-line measuring device 1,especially an in-line measuring device embodied as a Coriolis, massflow, and/or density, measuring device, which serves for registering amass flow m of a medium flowing in a pipeline (not shown) and forrepresenting such in a mass flow, measured value representing this massflow instantaneously. The medium can be practically any flowablematerial, for example, a powder, a liquid, a gas, a vapor, or the like.Alternatively or in supplementation, the in-line measuring device 1 can,in given cases, also be used for measuring a density ρ and/or aviscosity η of the medium. Especially, the in-line measuring device isprovided for measuring media, such as e.g. petroleum, natural gas orother petrochemical materials, which are flowing in a pipeline having acaliber greater than 250 mm, especially a caliber of 300 mm or more.Especially, the in-line measuring device is additionally provided formeasuring flowing media of the aforementioned type, which are caused toflow with a mass flow rate of greater than 2200 t/h, especially greaterthan 2500 t/h.

The in-line measuring device 1 comprises, for such purpose: A measuringtransducer 11 of vibration-type, through which the medium being measuredflows, during operation; as well as, electrically connected with themeasuring transducer 11, a measuring device electronics 12, which ishere not shown in detail, but, instead only schematically in the form ofa contained unit. In advantageous manner, the measuring deviceelectronics 12 is so designed that, during operation of the in-linemeasuring device 1, it can exchange measuring, and/or other operating,data with a measured value processing unit superordinated to it, forexample, a programmable logic controller (PLC), a personal computerand/or a work station, via a data transmission system, for example, ahardwired fieldbus system and/or wirelessly per radio. Furthermore, themeasuring device electronics 12 is so designed, that it can be fed by anexternal energy supply, for example, also via the aforementionedfieldbus system. For the case, in which the in-line measuring device 1is provided for coupling to a fieldbus, or other communication, system,the measuring device electronics 12, especially a programmable measuringdevice electronics, includes, additionally, a correspondingcommunication interface for data communication, e.g. for sending themeasured data to the already mentioned, programmable logic controller ora superordinated process control system.

FIGS. 4, 5 a, 5 b, 6 a, 6 b, 7, 8 a, 8 b show different representationsof examples of embodiments for a measuring transducer 11 ofvibration-type suited for the in-line measuring device 1, especially oneserving as a Coriolis, mass flow, density and/or viscosity, transducer,which measuring transducer 11 is applied, during operation, in thecourse of a pipeline (not shown), through which a medium to be measured,for example, a powdered, liquid, gaseous or vaporous medium, is flowing.The measuring transducer 11 serves to produce, as already mentioned, ina medium flowing therethrough, such mechanical reaction forces,especially Coriolis forces dependent on mass flow, inertial forcesdependent on density of the medium and/or frictional forces dependent onviscosity of the medium, which react measurably, especially registerablyby sensor, on the measuring transducer. Derived from these reactionforces describing the medium, by means of evaluating methodscorrespondingly implemented in the measuring device electronics inmanner known to those skilled in the art, e.g. the mass flow, thedensity and/or the viscosity of the medium can be measured.

The measuring transducer 11 includes a transducer housing 7 ₁, which is,here, essentially tubular, and externally circularly cylindrical, andwhich serves, among other things, also as a support frame, in whichother components of the measuring transducer 11 serving for registeringthe at least one measured variable are accommodated to be protectedagainst external, environmental influences. In the example of anembodiment shown here, at least one middle segment of the transducerhousing 7 ₁ is formed by means of a straight, especially circularlycylindrical, tube, so that, for manufacture of the transducer housing,for example, also cost effective, welded or cast, standard tubes, forexample, of cast steel or forged steel, can be used.

An inlet-side, first housing end of the transducer housing 7 ₁ is formedby means of an inlet-side, first flow divider 20 ₁ and an outlet-side,second housing end of the transducer housing 7 ₁ is formed by means ofoutlet-side, second flow divider 20 ₂. Each of the two flow dividers 20₁, 20 ₂, which are, in this respect, formed as integral components ofthe housing, includes exactly four, for example, circularly cylindricalor tapered or conical, flow openings 20 _(1A), 20 _(1B), 20 _(1C), 20_(1D), or 20 _(2A), 20 _(2B), 20 _(2C), 20 _(2D), each spaced from oneanother and/or each embodied as an inner cone.

Moreover, each of the flow dividers 20 ₁, 20 ₂, for example,manufactured of steel, is provided with a flange 6 ₁, or 6 ₂, forexample, manufactured of steel, for connecting of the measuringtransducer 11 to a tubular segment of the pipeline serving for supplyingmedium to the measuring transducer, or to a tubular segment of suchpipeline serving for removing medium from the measuring transducer. Eachof the two flanges 6 ₁, 6 ₂ has, according to an embodiment of theinvention, a mass of more than 50 kg, especially more than 60 kg and/orless than 100 kg. For leakage free, especially fluid tight, connectingof the measuring transducer with the, in each case, correspondingtubular segment of the pipeline, each of the flanges includesadditionally, in each case, a corresponding, as planar as possible,sealing surface 6 _(1A), or 6 _(2A). A distance between the two sealingsurfaces 6 _(1A), 6 _(2A) of both flanges defines, thus, for practicalpurposes, an installed length, L₁₁, of the measuring transducer 11. Theflanges are dimensioned, especially as regards their inner diameter,their respective sealing surface as well as the flange bores serving foraccommodating corresponding connection bolts, according to the nominaldiameter D₁₁ provided for the measuring transducer 11 as well as thetherefor, in given cases, relevant industrial standards, correspondingto a caliber of the pipeline, in whose course the measuring transduceris to be used.

As a result of the large nominal diameter lastly desired for themeasuring transducer, its installed length L₁₁ amounts, according to anembodiment of the invention, to more than 1200 mm. Additionally, it is,however, provided that the installed length of the measuring transducer11 is kept as small as possible, especially smaller than 3000 mm. Theflanges 6 ₁, 6 ₂ can, as well as also directly evident from FIG. 4 andsuch as quite usual in the case of such measuring transducers, bearranged, for this purpose, as near as possible to the flow openings ofthe flow dividers 20 ₁, 20 ₂, in order so to provide an as short aspossible inlet, or outlet, as the case may be, region in the flowdividers and, thus, in total, to provide an as short as possibleinstalled length L₁₁ of the measuring transducer, especially aninstalled length L₁₁ of less than 3000 mm. For an as compact as possiblemeasuring transducer with an also in the case of desired high mass flowrates of over 2200 t/h, according to another embodiment of theinvention, the installed length and the nominal diameter of themeasuring transducer are so dimensioned, matched to one another, that anominal diameter to installed length ratio D₁₁/L₁₁ of the measuringtransducer, as defined by a ratio of the nominal diameter D₁₁ of themeasuring transducer to the installed length L₁₁ of the measuringtransducer is smaller than 0.3, especially smaller than 0.2 and/orgreater than 0.1.

In an additional embodiment of the measuring transducer, the transducerhousing comprises an essentially tubular, middle segment. Additionally,it is provided that the transducer housing is so dimensioned, that ahousing inner diameter to nominal diameter ratio of the measuringtransducer defined by a ratio of the largest housing inner diameter tothe nominal diameter of the measuring transducer is, indeed, greaterthan 0.9, however, smaller than 1.5, as much as possible, however,smaller than 1.2.

In the case of the here illustrated example of an embodiment, thereadjoin on the inlet and outlet sides of the middle segment,additionally, likewise tubular end segments of the transducer housing.For the case illustrated in the example of an embodiment, in which themiddle segment and the two end segments, as well as also the flowdividers connected with the respective flanges in the inlet and outletregions all have the same inner diameter, the transducer housing can inadvantageous manner also be formed by means of a one piece, for example,cast or forged, tube, on whose ends the flanges are formed or welded,and in the case of which the flow dividers are formed by means of plateshaving the flow openings, especially plates somewhat spaced from theflanges and welded to the inner wall orbitally and/or by means of laser.Especially for the case, in which the mentioned housing inner diameterto nominal diameter ratio of the measuring transducer is selected equalto one, for manufacture of the transducer housing, for example, a tubematched to the pipeline to be connected to as regards caliber, wallthickness and material and, in that respect, also as regards the allowedoperating pressure and having a length correspondingly matching theselected measuring tube length can be used. For simplifying thetransport of the measuring transducer, or the totally therewith formed,in-line measuring device, additionally, such as, for example, alsoprovided in the initially mentioned U.S. Pat. No. 7,350,421, transporteyes can be provided affixed on the inlet side and on the outlet sideexternally on the transducer housing.

For conveying the medium flowing, at least at times, through pipelineand measuring transducer, the measuring transducer of the inventioncomprises, additionally, exactly four, straight, measuring tubes 18 ₁,18 ₂, 18 ₃, 18 ₄ held oscillatably in the transducer housing 10,especially measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, which are parallelrelative to one another and/or equally long, which, during operation, ineach case, communicate with the pipeline and, at least at times, arecaused to vibrate in at least one oscillatory mode, the so-called wantedmode, suited for ascertaining the physical, measured variable.Especially suited as wanted mode and naturally inherent to each of themeasuring tubes 18 ₁, 18 ₂, 18 ₃, and 18 ₄ is a bending oscillation,fundamental mode, which at a minimum bending oscillation, resonancefrequency, f18 ₁, f18 ₂, f18 ₃, or f18 ₄, has exactly one oscillatoryantinode.

Of the four—here essentially circularly cylindrical, of equal length andparallel relative to one another as well as to the above mentioned,middle tubular segment of the transducer housing—measuring tubes, afirst measuring tube 18 ₁ opens with an inlet-side, first measuring tubeend into a first flow opening 20 _(1A) of the first flow divider 20 ₁and with an outlet-side, second measuring tube end into a first flowopening 20 _(2A) of the second flow divider 20 ₂, a second measuringtube 18 ₂ opens with an inlet-side, first measuring tube end into asecond flow opening 20 _(1B) of the first flow divider 20 ₁ and with anoutlet-side, second measuring tube end into a second flow opening 20_(2B) of the second flow divider 20 ₂, a third measuring tube 18 ₃ openswith an inlet-side, first measuring tube end into a third flow opening20 _(1C) of the first flow divider 20 ₁ and with an outlet-side, secondmeasuring tube end into a third flow opening 20 _(2C) of the second flowdivider 20 ₂ and a fourth measuring tube 18 ₄ opens with an inlet-side,first measuring tube end into a fourth flow opening 20 _(1D) of thefirst flow divider 20 ₁ and with an outlet-side, second measuring tubeend into a fourth flow opening 20 _(2D) of the second flow divider 20 ₂.The four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are, thus, connected tothe flow dividers 20 ₁, 20 ₂, especially equally constructed flowdividers 20 ₁, 20 ₂, to form flow paths connected in parallel, and,indeed, in a manner enabling vibrations, especially bendingoscillations, of the measuring tubes relative to one another, as well asalso relative to the transducer housing. Additionally, it is provided,that the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are held in thetransducer housing 7 ₁ only by means of said flow dividers 20 ₁, 20 ₂.

The measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, or a therewith formed, innerpart of the measuring transducer 11, are, such as directly evident fromthe combination of FIGS. 1, 2 and 4 and such as also usual in the caseof such measuring transducers, encased by the transducer housing 7 ₁, inthe illustrated case practically completely. Transducer housing 7 ₁serves, in this regard, thus not only as support frame or holder of themeasuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, but also for protecting them, aswell as also other components of the measuring transducer placed withinthe transducer housing 7 ₁, from external environmental influences, suchas e.g. dust or water spray. Moreover, the transducer housing 7 ₁ canadditionally also be so embodied and so dimensioned, that it can, in thecase of possible damage to one or a plurality of the measuring tubes,e.g. through crack formation or bursting, completely retain outflowingmedium up to a required maximum positive pressure in the interior of thetransducer housing 7 ₁ as long as possible, wherein such critical statecan, such as, for example, also indicated in the initially mentionedU.S. Pat. No. 7,392,709, be registered and signaled by means ofcorresponding pressure sensors and/or on the basis of operatingparameters produced internally, during operation, by the mentionedmeasuring device electronics. Used as material for the transducerhousing 7 ₁ can be, accordingly, especially, steels, such as, forinstance, structural steel, or stainless steel, or also other suitable,or usually suitable for this application, high strength materials.

According to an embodiment of the invention, the four measuring tubes 18₁, 18 ₂, 18 ₃, 18 ₄ are additionally so embodied and so installed in themeasuring transducer 11, that at least the minimum bending oscillation,resonance frequencies f18 ₁, f18 ₂ of the first and second measuringtubes 18 ₁, 18 ₂ are essentially equal and at least the minimum bendingoscillation, resonance frequencies f18 ₃, f18 ₄ of the third and fourthmeasuring tubes 18 ₃, 18 ₄ are essentially equal.

According to an additional embodiment of the invention, at least thefirst and second measuring tubes 18 ₁, 18 ₂ are of equal construction asregards a material, of which their tube walls are composed, and/or asregards their geometric tube dimensions, especially a tube length, atube wall thickness, a tube outer diameter and/or a caliber.Additionally, also at least the third and fourth measuring tubes 18 ₃,18 ₄ are of equal construction as regards a material, of which theirtube walls are composed, and/or as regards their geometric tubedimensions, especially a tube length, a tube wall thickness, a tubeouter diameter and/or a caliber, so that, as a result, the fourmeasuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are, at least pairwise,essentially of equal construction. According to an additional embodimentof the invention, it is, in such case, additionally provided, toconstruct both the third measuring tube as well as also the fourthmeasuring tube, such that the two measuring tubes are different from thefirst measuring tube and from the second measuring tube, as regardstheir respective geometric tube dimensions, especially a tube length, atube wall thickness, a tube outer diameter and/or a caliber, especiallyin such a manner, that the minimum bending oscillation, resonancefrequencies of the four measuring tubes are only pairwise equal. Throughthe, thus, created symmetry breaking in the case of the four measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, among other things, the sensitivity, theoscillatory behavior, especially the mechanical eigenfrequencies, and/orthe cross sensitivity to the primary, measuring influencing, disturbancevariables, such as, for instance, a temperature, or pressure,distribution, the loading of the medium with impurities, etc., of thetwo, in this respect, mutually different, measuring tube pairs 18 ₁, 18₂, or 18 ₃, 18 ₄, can be matched, with targeting, to one another and,thus, an improved diagnosis of the measuring transducer, duringoperation, can be enabled. Of course, the four measuring tubes 18 ₁, 18₂, 18 ₃, 18 ₄ can, in case required, however, also be of equalconstruction as regards a material, of which their tube walls arecomposed, and/or as regards their geometric tube dimensions, especiallya tube length, a tube wall thickness, a tube outer diameter and/or acaliber, especially in such a manner, that, as a result, the minimumbending oscillation, resonance frequencies of all four measuring tubes18 ₁, 18 ₂, 18 ₃, 18 ₄ are essentially equal.

Suited as material for the tube walls of the measuring tubes is, again,especially, titanium, zirconium or tantalum. However, serving asmaterial for the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ can be alsopractically any other therefor usually applied, or at least suitable,material, especially such with a thermal expansion coefficient as smallas possible and a yield point as high as possible. For most applicationsof industrial measurements technology, especially also in thepetrochemical industry, consequently, also measuring tubes of stainlesssteel, for example, also duplex steel or super duplex steel, wouldsatisfy the requirements as regards mechanical strength, chemicalresistance as well as thermal requirements, so that in numerous cases ofapplication of the transducer housing 7 ₁, the flow dividers 20 ₁, 20 ₂,as well as also the tube walls of the measuring tubes 18 ₁, 18 ₂, 18 ₃,18 ₄ can, in each case, be made of steel of, in each case, sufficientlyhigh quality, this being of advantage, especially as regards material,and manufacturing, costs, as well as also as regards the thermallyrelated dilation behavior of the measuring transducer 11, duringoperation.

In an additional advantageous embodiment of the invention, the flowopenings of the first flow divider 20 ₁ are additionally so arranged,that imaginary areal centers of gravity, which belong to the crosssectional areas, here, circularly shaped cross sectional areas, of theflow openings of the first flow divider lying in a shared, imaginary,cutting plane of the first flow divider extending perpendicularly to alongitudinal axis of the measuring transducer, especially a longitudinalaxis parallel to a principal flow axis of the measuring transducer, formthe vertices of an imaginary square. Additionally, the flow openings ofthe second flow divider 20 ₂ are so arranged, that imaginary arealcenters of gravity belonging to the, here, likewise circularly shaped,cross sectional areas of the flow openings of the second flow divider 20₂ form the vertices of an imaginary square, wherein such cross sectionalareas lie, in turn, in a shared, imaginary, cutting plane of the secondflow divider extending perpendicularly to a longitudinal axis of themeasuring transducer, especially a longitudinal axis parallel to aprincipal flow axis of the measuring transducer. As a result of this, anenvelope the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ formsessentially a right cuboid-like body with a square-like base having aquadruple symmetry, whereby the space requirement of the inner partformed by means of the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ canbe minimized in a manner supporting the compactness of the measuringtransducer 11 as a whole.

According to an additional embodiment of the invention, each of themeasuring tubes is additionally so arranged in the measuring transducer,that a smallest lateral separation of each of the four measuring tubes(here, of equal length) from a housing side wall of the transducerhousing is, in each case, greater than zero, especially, however,greater than 3 mm and/or greater than twice a respective tube wallthickness, or that a smallest lateral separation between two neighboringmeasuring tubes is, in each case, greater than 3 mm and/or greater thanthe sum of their respective tube wall thicknesses. Accordingly,additionally, each of the flow openings is so arranged, that a smallestlateral separation of each of the flow openings from a housing side wallof the transducer housing 7 ₁ is, in each case, greater than zero,especially greater than 3 mm and/or greater than twice a smallest tubewall thickness of the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, or that asmallest lateral separation between the flow openings is greater than 3mm and/or greater than twice a smallest tube wall thickness of themeasuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄. For such purpose, according toan additional embodiment of the invention, the four measuring tubes 18₁, 18 ₂, 18 ₃, 18 ₄ and the transducer housing 7 ₁ are so dimensionedand matched to one another, that a housing to measuring tube, innerdiameter ratio of the measuring transducer, as defined by a ratio of thelargest housing inner diameter to a caliber at least of the firstmeasuring tube is greater than 3, especially greater than 4 and/orsmaller than 5.

As already initially mentioned, in the case of the measuring transducer11, the reaction forces required for the measuring are effected in themedium being measured by causing the measuring tubes 18 ₁, 18 ₂, 18 ₃,18 ₄ to oscillate in the so-called wanted mode. For such purpose, themeasuring transducer comprises additionally an exciter mechanism 5formed by means of at least one electromechanical, for example,electrodynamic, oscillation exciter acting on the measuring tubes 18 ₁,18 ₂, 18 ₃, 18 ₄, and serving for causing each of the measuring tubes,operationally, at least at times, to execute, and to maintain,oscillations suitable, in each case, for the particular measuring,especially bending oscillations, in the so-called wanted mode, with, ineach case, sufficiently large oscillation amplitude for producing andregistering the above named reaction forces in the medium. The at leastone oscillation exciter serves, in such case, especially for convertingan electrical excitation power P_(exc) fed from a correspondingmeasuring, and operating, circuit e.g. of the above named Coriolis, massflow meter into such, e.g. pulsating or harmonic, exciter forces Fexc,which act, as simultaneously as possible, uniformly, however, withopposite sense, on the measuring tubes. The exciter forces F_(exc) canbe tuned, in manner known, per se, to those skilled in the art, by meansprovided in the already mentioned measuring, and operating, electronics,e.g. by means of an electrical current, and/or voltage, control circuit,as regards their amplitude, and e.g. by means of phase control loop(PLL), as regards their frequency; compare, for this, for example, alsoU.S. Pat. No. 4,801,897 or U.S. Pat. No. 6,311,136.

As a result of medium flowing through the measuring tubes excited tooscillations in the wanted mode, there are induced in the mediumCoriolis forces, which, in turn, effect deformations of the measuringtubes corresponding to an additional, higher oscillation mode of themeasuring tubes, the so-called Coriolis mode. For example, the measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ can, during operation, be excited, by theelectromechanical exciter mechanism acting thereon, to bendingoscillations, especially to an instantaneous mechanical eigenfrequencyof the inner part formed by means of the four measuring tubes 18 ₁, 18₂, 18 ₃, 18 ₄, in the case of which they are—at leastpredominantly—laterally deflected in respective planes of oscillationand, such as directly evident from the combination of FIGS. 3 a, 3 b, or6 a, 6 b, are caused to oscillate pairwise in a shared plane ofoscillation XZ₁, or XZ₂, relative to one another with essentiallyopposite phase. This, in particular, in such a manner, that vibrationsexecuted by each of the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, duringoperation, simultaneously, are developed, at least at times, and/or atleast partially, in each case, as bending oscillations about animaginary, measuring tube longitudinal axis connecting the first andthe, in each case, associated second measuring tube end of therespective measuring tube, wherein the four measuring tube longitudinalaxes extend, in the here illustrated example of an embodiment with fourmutually parallel measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ equallyparallel relative to one another, such as do the measuring tubes 18 ₁,18 ₂, 18 ₃, 18 ₄, and, moreover, also essentially parallel to animaginary longitudinal axis of the total measuring transducerimaginarily connecting the two flow dividers and extending through acenter of mass of the measuring transducer. In other words, themeasuring tubes can, such as quite usual in the case of measuringtransducers of vibration-type, in each case, at least sectionally, becaused to oscillate in a bending oscillation mode in the manner of astring clamped on both ends. Accordingly, in an additional embodiment,the first and second measuring tubes 18 ₁, 18 ₂ are caused, in eachcase, to execute bending oscillations, which lie in a shared first planeof oscillation XZ₁, and, thus, are essentially coplanar. Additionally,it is provided that the third and fourth measuring tubes 18 ₃, 18 ₄equally oscillate in a shared, second plane of oscillation XZ₂,especially one essentially parallel to the first plane of oscillationXZ₁, with opposite phase relative to one another; compare, for this,also FIGS. 6 a, 6 b.

In an additional embodiment of the invention, the measuring tubes 18 ₁,18 ₂, 18 ₃, 18 ₄ are excited by means of the exciter mechanism 5, duringoperation, at least partially, especially predominantly, to bendingoscillations, which have a bending oscillation frequency, which is aboutequal to an instantaneous mechanical resonance frequency of the innerpart comprising the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ or whichat least lies in the vicinity of such an eigen-, or resonance,frequency. The instantaneous mechanical bending oscillation resonancefrequencies are, in such case, as is known, dependent in special measureon size, shape and material of the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18₄, as well as also on an instantaneous density of the medium flowingthrough the measuring tubes, and can, thus, during operation of themeasuring transducer, be variable within a wanted frequency band havingan expanse of several kilohertz. In the exciting of the measuring tubesto a bending oscillation resonance frequency, on the one hand, anaverage density of the medium instantaneously flowing through the fourmeasuring tubes can be easily ascertained on the basis of theinstantaneously excited oscillation frequency. On the other hand, also,in such manner, the electrical power instantaneously required formaintaining the oscillations excited in the wanted mode can beminimized. Especially, the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄,driven by the exciter mechanism, additionally, are, at least at times,caused to oscillate with essentially equal oscillation frequency,especially at a shared natural mechanical eigenfrequency of the innerpart. Moreover, it is provided that the measuring tubes 18 ₁, 18 ₂, 18₃, 18 ₄, caused to oscillate at essentially equal frequency, are soexcited, that, at least in the case of no flowing medium, the first andthird measuring tubes 18 ₁, 18 ₃ oscillate essentially synchronouslyrelative to one another, i.e. with essentially equal oscillation form,essentially equal phase position and about equal oscillation amplitude.In manner analogous thereto, in the case of this embodiment of theinvention, also the second and fourth measuring tubes 18 ₂, 18 ₄ arecaused to oscillate essentially synchronously relative to one another.

The exciter mechanism according to an embodiment of the invention, isembodied in such a manner that, therewith, the first measuring tube 18 ₁and the second measuring tube 18 ₂ are excitable, during operation, toopposite phase, bending oscillations in the shared first plane ofoscillation XZ₁ and the third measuring tube 18 ₃ and the fourthmeasuring tube 18 ₄, during operation, to opposite phase bendingoscillations in the shared second plane of oscillation XZ₂, especially ashared second plane of oscillation XZ₂ essentially parallel to the firstplane of oscillation XZ₁. In an additional embodiment of the invention,the exciter mechanism 5 is formed therefor by means of a firstoscillation exciter 5 ₁, especially an electrodynamic, first oscillationexciter 5 ₁ and/or a first oscillation exciter 5 ₁ differentiallyexciting oscillations of the first measuring tube 18 ₁ relative to thesecond measuring tube 18 ₂.

Additionally, it is provided, that the first oscillation exciter 5 ₁ isan oscillation exciter of electrodynamic type acting simultaneously,especially differentially, on at least two of the measuring tubes 18 ₁,18 ₂, 18 ₃, 18 ₄. Accordingly, the first oscillation exciter 5 ₁ isformed additionally by means of a permanent magnet held on the firstmeasuring tube and a cylindrical coil permeated by the magnetic field ofthe permanent magnet and held on the second measuring tube, especiallyin such a manner of a coil, plunging arrangement, in the case of whichthe cylindrical coil is arranged coaxially to the permanent magnet andthe permanent magnet is embodied in the form of an armature movedplungingly within the coil. In a further development of the invention,the exciter mechanism comprises additionally a second oscillationexciter 5 ₂, especially an electrodynamic, second oscillation exciter 5₂ and/or a second oscillation exciter 5 ₂ constructed equally to thefirst oscillation exciter 5 ₁ and/or differentially excitingoscillations of the third measuring tube 18 ₃ relative to the fourthmeasuring tube 18 ₄. The two oscillation exciters can, in advantageousmanner, be interconnected electrically in series, especially in such amanner, that a combined driver signal excites oscillations of the firstand third measuring tubes 18 ₁, 18 ₃ together relative to the second andfourth measuring tubes 18 ₂, 18 ₄. In an additional embodiment, thesecond oscillation exciter 5 ₂ is formed by means of a permanent magnetheld on the third measuring tube and a cylindrical coil permeated by themagnetic field of the permanent magnet and held on the fourth measuringtube.

As shown in FIG. 4, the first oscillation exciter 5 ₁ is arranged inabove the first and second measuring tubes 18 ₁, 18 ₂ and, thus, alsoabove a combined local center of gravity of all four measuring tubes 18₁, 18 ₂, 18 ₃, 18 ₄, which lies in an imaginary cross sectional planepassing through the installed position of said oscillation exciter,whose inner part is formed by means of the four measuring tubes. As aresult of the arrangement of at least one oscillation exciter of theexciter mechanism 5 outside of the above described combined center ofgravity of the four measuring tubes, supplementally to bendingoscillations, in advantageous manner, also wanted torsional oscillationscan be excited, simultaneously or intermittently. In this way, in mediuminstantaneously located in the measuring tubes 18 ₁, 18 ₂, 18 ₃, and 18₄, respectively, in considerable measure, also frictional, or shear,forces, principally dependent on viscosity, can be induced, which, inturn, react dampingly and, thus, measurably, on the oscillations of themeasuring tubes 18 ₁, 18 ₂, 18 ₃, and 18 ₄, respectively. Based thereon,for example, on the basis of the driver signal fed into the excitermechanism 5, especially its electrical current level, in case required,also a viscosity of the medium guided in the measuring transducer can beascertained.

It is noted here, additionally, that, although the oscillation exciterof the exciter mechanism illustrated in the example of an embodimentacts, in each case, about centrally on the measuring tubes,alternatively or in supplementation also oscillation exciters acting onthe inlet and on the outlet sides on the respective measuring tubes canbe used, for instance in the manner of the exciter mechanisms proposedin U.S. Pat. No. 4,823,614, U.S. Pat. No. 4,831,885, or US-A2003/0070495.

As evident from FIGS. 2 and 4 and usual in the case of measuringtransducers of the type being discussed, additionally provided in themeasuring transducer 11 is a sensor arrangement 19, for example, anelectrodynamic sensor arrangement, reacting to vibrations of themeasuring tubes 18 ₁, 18 ₂, 18 ₃, or 18 ₄, especially inlet, andoutlet-side vibrations, especially bending oscillations excited by meansof the exciter mechanism 5, for producing oscillation measurementsignals representing vibrations, especially bending oscillations, of themeasuring tubes and influenced, for example, as regards a frequency, asignal amplitude and/or a phase position—relative to one another and/orrelative to the driver signal—by the measured variable to be registered,such as, for instance, the mass flow rate and/or the density and aviscosity of the medium, respectively.

In an additional embodiment of the invention, the sensor arrangement isformed by means of an inlet-side, first oscillation sensor 19 ₁,especially an electrodynamic, first oscillation sensor and/or a firstoscillation sensor differentially registering at least oscillations ofthe first measuring tube 18 ₁ relative to the second measuring tube 18₂, as well as an outlet-side, second oscillation sensor 19 ₂, especiallyan electrodynamic, second oscillation sensor and/or a second oscillationsensor differentially registering at least oscillations of the firstmeasuring tube 18 ₁ relative to the second measuring tube 18 ₂, whichtwo oscillation sensors deliver, respectively, a first, and a second,oscillation measurement signal reacting to movements of the measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, especially their lateral deflectionsand/or deformations. This, especially, in such a manner, that at leasttwo of the oscillation measurement signals delivered by the sensorarrangement 19 have a phase shift relative to one another, whichcorresponds to, or depends on, the instantaneous mass flow rate of themedium flowing through the measuring tubes, as well as, in each case, asignal frequency, which depends on an instantaneous density of themedium flowing in the measuring tubes. The two oscillation sensors 19 ₁,19 ₂, for example, oscillation sensors constructed equally to oneanother, can, for such purpose—such as quite usual in the case ofmeasuring transducers of the type being discussed—be placed essentiallyequidistantly from the first oscillation exciter 5 ₁ in the measuringtransducer 11. Moreover, the oscillation sensors of the sensorarrangement 19 can, at least, insofar as they are of equal constructionto that of the at least one oscillation exciter of the exciter mechanism5, work analogously to its principle of action, for example, thus belikewise of electrodynamic type. In a further development of theinvention, the sensor arrangement 19 is additionally formed also bymeans of an inlet-side, third oscillation sensor 19 ₃, especially anelectrodynamic, oscillation sensor and/or an oscillation sensordifferentially registering oscillations of the third measuring tube 18 ₃relative to the fourth measuring tube 18 ₄, as well as an outlet-side,fourth oscillation sensor 19 ₄, especially an electrodynamic, fourthoscillation sensor 19 ₄ and/or an electrodynamic oscillation sensordifferentially registering oscillations of the third measuring tube 18 ₃relative to the fourth measuring tube 18 ₄. For additional improving ofthe signal quality, as well as also for simplifying the measuring deviceelectronics 12 receiving the measurement signals, furthermore, the firstand third oscillation sensors 19 ₁, 19 ₃ can be electrically in seriesinterconnected, for example, in such a manner, that a combinedoscillation measurement signal represents combined inlet-sideoscillations of the first and third measuring tubes 18 ₁, 18 ₃ relativeto the second and fourth measuring tubes 18 ₂, 18 ₄. Alternatively or insupplementation, also the second and fourth oscillation sensors 19 ₂, 19₄ can be electrically in series interconnected in such a manner, that acombined oscillation measurement signal of both oscillation sensors 19₂, 19 ₄ represents combined outlet-side oscillations of the first andthird measuring tubes 18 ₁, 18 ₃ relative to the second and fourthmeasuring tubes 18 ₂, 18 ₄.

For the aforementioned case, that the oscillation sensors of the sensorarrangement 19, especially oscillation sensors constructed equally toone another, should register oscillations of the measuring tubesdifferentially and electrodynamically, the first oscillation sensor 19 ₁is formed by means of a permanent magnet held to the first measuringtube—here in the region of oscillations to be registered on the inletside—and a cylindrical coil permeated by the magnetic field of thepermanent magnet and held to the second measuring tube—herecorrespondingly likewise in the region of oscillations to be registeredon the inlet side—, and the second oscillation sensor 19 ₂ is formed bymeans of a permanent magnet held—in the region of oscillations to beregistered on the outlet side—to the first measuring tube and acylindrical coil permeated by the magnetic field of the permanent magnetand held to the second measuring tube—here correspondingly likewise inthe region of oscillations to be registered on the outlet side. Equally,additionally also the, in given cases, provided, third oscillationsensor 19 ₃ can correspondingly be formed by means of a permanent magnetheld to the third measuring tube and a cylindrical coil permeated by themagnetic field of the permanent magnet and held to the fourth measuringtube, and the, in given cases, provided, fourth oscillation sensor 19 ₄by means of a permanent magnet held to the third measuring tube and acylindrical coil permeated by the magnetic field of the permanent magnetand held to the fourth measuring tube.

It is to be noted here additionally that, although, in the case of theoscillation sensors of the sensor arrangement 19 illustrated in theexample of an embodiment, the oscillation sensor is, in each case, ofelectrodynamic type, thus, in each case, formed by means of acylindrical magnet coil affixed to one of the measuring tubes and atherein plunging permanent magnet correspondingly affixed to anoppositely lying measuring tube, additionally also other oscillationsensors known to those skilled in the art, such as e.g. optoelectronicsensors, can be used for forming the sensor arrangement. Furthermore,such as quite usual in the case of measuring transducers of the typebeing discussed, supplementally to the oscillation sensors, other,especially auxiliary sensors, or sensors registering disturbancevariables, can be provided in the measuring transducer, such as e.g.acceleration sensors, pressure sensors and/or temperature sensors, bymeans of which, for example, the ability of the measuring transducer tofunction and/or changes of the sensitivity of the measuring transducerto the measured variables primarily to be registered, especially themass flow rate and/or the density, as a result of cross sensitivities,or external disturbances, can be monitored and, in given cases,correspondingly compensated.

For assuring an as high as possible sensitivity of the measuringtransducer to the mass flow, according to an additional embodiment ofthe invention, the oscillation sensors are so arranged on the measuringtubes in the measuring transducer, that a measuring length, L₁₉, of themeasuring transducer corresponding to a minimum separation between thefirst oscillation sensor 19 ₁ and the second oscillation sensor 19 ₂,amounts to more than 500 mm, especially more than 600 mm.

The exciter mechanism 5 and the sensor arrangement 19 are additionally,such as usual in the case of such measuring transducers, coupled insuitable manner (for example, hardwired by means of corresponding cableconnections) with a measuring, and operating, circuit correspondinglyprovided in the measuring device electronics. The measuring, andoperating, circuit, in turn, produces, on the one hand, an excitersignal correspondingly driving the exciter mechanism 5, for example, anexciter signal controlled as regards an exciter current and/or anexciter voltage. On the other hand, the measuring, and operating,circuit receives the oscillation measurement signals of the sensorarrangement 19 and generates, therefrom, sought measured values, which,for example, can represent a mass flow rate, a totaled mass flow, adensity and/or a viscosity of the medium being measured and which, ingiven cases, can be displayed on-site and/or also sent to a dataprocessing system superordinated to the in-line measuring device, in theform of digital, measured data and there correspondingly furtherprocessed. The above mentioned application of differentially acting,oscillation exciters, or oscillation sensors, in the case of the hereillustrated inner part, introduces, among other things, also theadvantage, that for operating the measuring transducer of the invention,also such established measuring, and operating, electronics can be used,such as have found broad application, for example, already inconventional Coriolis, mass flow and/or density measuring devices.

The measuring device electronics 12, including the measuring, andoperating, circuit, can, furthermore, be accommodated, for example, in aseparate electronics housing 7 ₂, which is arranged removed from themeasuring transducer or, such as shown in FIG. 1, is affixed directly onthe measuring transducer 1, for example, externally on the transducerhousing 7 ₁, in order to form a single compact device. In the case ofthe here illustrated example of an embodiment, consequently, placed onthe transducer housing 7 ₁ is, additionally, a neck-like, transitionpiece serving for holding the electronics housing 7 ₂. Within thetransition piece can additionally be arranged a feedthrough for theelectrical connecting lines between measuring transducer 11, especiallythe therein placed oscillation exciters and sensors, and the mentionedmeasuring device electronics 12. The feedthrough is manufactured to behermetically sealed and/or pressure resistant, for example, by means ofglass, and/or plastic potting compound.

As already multiply mentioned, the in-line measuring device and, thus,also the measuring transducer 11, is provided, especially, formeasurements also of high mass flows of more than 2200 t/h in a pipelineof large caliber of more than 250 mm. Taking this into consideration,according to an additional embodiment of the invention, the nominaldiameter of the measuring transducer 11, which, as already mentioned,corresponds to a caliber of the pipeline, in whose course the measuringtransducer 11 is to be used, is so selected, that it amounts to morethan 100 mm, especially, however, is greater than 300 mm. Additionally,according to a further embodiment of the measuring transducer, it isprovided, that each of the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ has,in each case, a caliber D₁₈ corresponding to a particular tube innerdiameter, which amounts to more than 60 mm. Especially, the measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are additionally so embodied, that each hasa caliber D₁₈ of more than 80 mm. Alternatively thereto or insupplementation thereof, the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are,according to another embodiment of the invention, additionally sodimensioned, that they have, in each case, a measuring tube length L₁₈of at least 1000 mm. The measuring tube length L₁₈ corresponds, in thehere illustrated example of an embodiment with equal length measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, in each case, to a minimum separationbetween the first flow opening 20 _(1A) of the first flow divider 20 ₁and the first flow opening 20 _(2A) of the second flow divider 20 ₂.Especially, the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are, in suchcase, so designed, that their measuring tube length L₁₈ is, in eachcase, greater than 1200 mm.

Accordingly, there results, at least for the mentioned case, that themeasuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are composed of steel, in thecase of the usually used wall thicknesses of over 1 mm, a mass of, ineach case, at least 20 kg, especially more than 30 kg. One tries,however, to keep the empty mass of each of the measuring tubes 18 ₁, 18₂, 18 ₃, 18 ₄ smaller than 50 kg.

In consideration of the fact that, as already mentioned, each of themeasuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, in the case of the measuringtransducer of the invention, weighs well over 20 kg and, in such case,such as directly evident from the above dimensional specifications, canhave a capacity of easily 10 l or more, the inner part comprising thenthe four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ can, at least in thecase of medium with high density flowing through, reach a total mass offar over 80 kg. Especially in the case of the application of measuringtubes with comparatively large caliber D₁₈, large wall thickness andlarge measuring tube length L₁₈, the mass of the inner part formed bythe measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ can directly, however, alsobe greater than 100 kg or, at least with medium flowing through, e.g.oil or water, be more than 120 kg. As a result of this, an empty massM₁₁ of the measuring transducer amounts, in total, also to far more than200 kg, and, in the case of nominal diameters D₁₁ of significantlygreater than 250 mm, even more than 300 kg. As a result, the measuringtransducer of the invention can have a mass ratio M₁₁/M₁₈ of an emptymass M₁₁ of the total measuring transducer to an empty mass M₁₈ of thefirst measuring tube of easily greater than 10, especially greater than15.

In order, in the case of the mentioned high empty mass M₁₁ of themeasuring transducer, to employ the therefor, in total, applied materialas optimally as possible and, thus, to utilize the—most often also veryexpensive—material, in total, as efficiently as possible, according toan additional embodiment, the nominal diameter D₁₁ of the measuringtransducer is so dimensioned relative to its empty mass M₁₁, that a massto nominal diameter ratio M₁₁/D₁₁ of the measuring transducer 11, asdefined by a ratio of the empty mass M₁₁ of the measuring transducer 11to the nominal diameter D₁₁ of the measuring transducer 11, is smallerthan 2 kg/mm, especially as much as possible, however, smaller than 1kg/mm. In order to assure a sufficiently high stability of the measuringtransducer 11, the mass to nominal diameter ratio M₁₁/D₁₁ of themeasuring transducer 11 is, at least in the case use of the abovementioned conventional materials, however, to be chosen as much aspossible greater than 0.5 kg/mm. Additionally, according to anadditional embodiment of the invention, for additional improvement ofthe efficiency of the installed material, the mentioned mass ratioM₁₁/M₁₁ is kept smaller than 25.

For creation of a nevertheless as compact as possible measuringtransducer of sufficiently high oscillation quality factor and as littlepressure drop as possible, according to an additional embodiment of theinvention, the measuring tubes are so dimensioned relative to the abovementioned, installed length L₁₁ of the measuring transducer 11, that acaliber to installed length ratio D₁₈/L₁₁ of the measuring transducer,as defined by a ratio of the caliber D₁₈ at least of the first measuringtube to the installed length L₁₁ of the measuring transducer 11, amountsto more than 0.02, especially more than 0.05 and/or less than 0.09.Alternatively or in supplementation, the measuring tubes 18 ₁, 18 ₂, 18₃, 18 ₄ are so dimensioned relative to the above mentioned installedlength L₁₁ of the measuring transducer, that a measuring tube length toinstalled length ratio L₁₈/L₁₁ of the measuring transducer, as definedby a ratio of the measuring tube length L₁₈ at least of the firstmeasuring tube to the installed length L₁₁ of the measuring transducer,amounts to more than 0.7, especially more than 0.8 and/or less than0.95.

In case required, possibly or at least potentially, mechanical stressesand/or vibrations caused by the vibrating, especially in the mentionedmanner, relatively large dimensioned, measuring tubes at the inlet sideor at the outlet side in the transducer housing can e.g. be minimized byconnecting the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ with oneanother mechanically at least pairwise on the inlet side, and at leastpairwise on the outlet side, in each case, by means of coupling elementsserving as so-called node plates—in the following referred to ascoupling elements of first type. Moreover, by means of such couplingelements of first type, be it through their dimensioning and/or theirpositioning on the measuring tubes, mechanical eigenfrequencies of themeasuring tubes and, thus, also mechanical eigenfrequencies of the innerpart formed by means of the four measuring tubes as well as thereonplaced, additional components of the measuring transducer and, thus,also its oscillatory behavior, in total, can, with targeting, beinfluenced.

The coupling elements of first type serving as node plates can, forexample, be thin plates, or washers, manufactured especially from thesame material as the measuring tubes, which, in each case, correspondingwith the number and the outer dimensions of the measuring tubes to becoupled with one another, are provided with bores, in given cases,supplementally, slitted to the edge, so that the washers can first bemounted onto the respective measuring tubes 18 ₁, 18 ₂, 18 ₃, or 18 ₄and, in given cases, thereafter still be bonded to the respectivemeasuring tubes, for example, by hard soldering or welding.

Accordingly, the measuring transducer comprises, according to anadditional embodiment of the invention, a first coupling element 24 ₁ offirst type, which is affixed on the inlet side at least to the firstmeasuring tube and to the second measuring tube and spaced both from thefirst flow divider as well as also from the second flow divider forforming inlet-side, oscillation nodes at least for vibrations,especially bending oscillations, of the first measuring tube and forthereto opposite phase vibrations, especially bending oscillations, ofthe second measuring tube, as well as a second coupling element 24 ₂ offirst type, especially a second coupling element 24 ₂ constructedequally to the first coupling element, which is affixed on the outletside at least to the first measuring tube 18 ₁ and to the secondmeasuring tube 18 ₂ and spaced both from the first flow divider 20 ₁ aswell as also from the second flow divider 20 ₂, as well as also from thefirst coupling element 24 ₁, for forming outlet-side, oscillation nodesat least for vibrations, especially bending oscillations, of the firstmeasuring tube 18 ₁ and for thereto opposite phase vibrations,especially bending oscillations, of the second measuring tube 18 ₂. Asdirectly evident from FIG. 4, or FIGS. 5 a, 5 b, the first couplingelement 24 ₁ of first type is affixed on the inlet side also to thethird measuring tube 18 ₃ and to the fourth measuring tube 18 ₄ andspaced both from the first flow divider 20 ₁ as well as also from thesecond flow divider 20 ₂, for forming inlet-side, oscillation nodes alsofor vibrations, especially bending oscillations, of the third measuringtube 18 ₃ and for thereto opposite phase vibrations, especially bendingoscillations, of the fourth measuring tube 18 ₄, and the second couplingelement 24 ₂ of first type is affixed on the outlet side also to thethird measuring tube 18 ₃ and to the fourth measuring tube 18 ₄ andspaced both from the first flow divider 20 ₁ as well as also from thesecond flow divider 20 ₂, as well as also from the first couplingelement 24 ₁, for forming outlet-side, oscillation nodes at least forvibrations, especially bending oscillations, of the third measuring tube18 ₃ and for thereto opposite phase vibrations, especially bendingoscillations, of the fourth measuring tube 18 ₄, so that, as a result,all four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are mechanicallyconnected with one another by means of the first coupling element 24 ₁of first type as well as by means of the second coupling element 24 ₂ offirst type. Each of the two aforementioned coupling elements 24 ₁, 24 ₂of first type, especially coupling elements constructed equally to oneanother, is, according to an additional embodiment of the invention,plate shaped, especially in such a manner, that it has, as well as alsodirectly evident from the combination of figures, a rather rectangularor also square, basic shape or, however, that it has, rather, a round,an oval, a cross shaped or, such as, for example, also provided in US-A2006/028326₄, a rather H-shaped basic shape. Additionally, the twocoupling elements 24 ₁, 24 ₂ are oriented essentially parallel relativeto one another.

As directly evident from FIG. 4, or FIGS. 5 a, 5 b, the twoaforementioned coupling elements 24 ₁, 24 ₂ are additionally so embodiedand so placed in the measuring transducer, that a center of mass of thefirst coupling element 24 ₁ of first type has a distance to a center ofmass of the measuring transducer 11, which is essentially equal to adistance of a center of mass of the second coupling element 24 ₂ offirst type to said center of mass of the measuring transducer 11,especially in such a manner, that the two coupling elements 24 ₁, 24 ₂are, as a result, arranged symmetrically to a shared imaginary crosssectional plane, in each case, cutting centrally through the measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄.

For additionally increasing the degrees of freedom in the case ofoptimizing the oscillatory behavior of the inner part formed by means ofthe four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, the measuringtransducer 11 comprises, according to a further development of theinvention, additionally a third coupling element 24 ₃ of first type,which is affixed on the inlet side at least to the third measuring tube18 ₃ and to the fourth measuring tube 18 ₄ and spaced both from thefirst flow divider 20 ₁ as well as also from the second flow divider 20₂ for forming inlet-side, oscillation nodes at least for vibrations,especially bending oscillations, of the third measuring tube 18 ₃ andfor thereto opposite phase vibrations, especially bending oscillations,of the fourth measuring tube 18 ₄. Moreover, the measuring transducer 11comprises, in the case of this further development, a fourth couplingelement 24 ₄ of first type, especially a fourth coupling elementconstructed equally to the third coupling element 24 ₃ of first type,which fourth coupling element is affixed on the outlet side at least tothe third measuring tube 18 ₃ and to the fourth measuring tube 18 ₄ andspaced both from the first flow divider 20 ₁ as well as also from thesecond flow divider 20 ₂, as well as also from the third couplingelement 24 ₃ of first type, for forming outlet-side, oscillation nodesat least for vibrations, especially bending oscillations, of the thirdmeasuring tube 18 ₃ and for thereto opposite phase vibrations,especially bending oscillations, of the fourth measuring tube 18 ₄.

Each of the two aforementioned third and fourth coupling elements 24 ₃,24 ₄ of first type, especially third and fourth coupling elementsconstructed equally to one another, is embodied, according to anadditional embodiment of the invention, again, plate shaped, especiallyin such a manner, that it has a rectangular, square, round, cross shapedor H-shaped, basic shape. Additionally, the two aforementioned third andfourth coupling elements 24 ₃, 24 ₄ are oriented extending essentiallyparallel relative to one another.

As shown in FIG. 4, or in FIGS. 5 a, 5 b, the third coupling element 24₃ of first type is affixed on the inlet side also to the first measuringtube 18 ₁ and to the second measuring tube 18 ₂ and spaced both from thefirst flow divider 20 ₁ as well as also from the second flow divider 20₂, as well as also from the first coupling element of first type 24 ₁and the fourth coupling element 24 ₄ of first type is affixed on theoutlet side also to the first measuring tube and to the second measuringtube and spaced both from the first flow divider as well as also fromthe second flow divider, as well as also from the second couplingelement, so that, as a result, all four measuring tubes 18 ₁, 18 ₂, 18₃, 18 ₄ are also mechanically connected with one another by means of thethird coupling element 24 ₃ of first type as well as by means of thefourth coupling element 24 ₄ of first type.

As directly evident from the combination of FIGS. 4, 5 a, 5 b, also thethird and fourth coupling elements 24 ₃, 24 ₄ are additionally soembodied and so placed in the measuring transducer, that a center ofmass of the third coupling element 24 ₃ of first type has a distance tothe center of mass of the measuring transducer, which essentially isequal to a distance of a center of mass of the fourth coupling element24 ₄ of first type to said center of mass of the measuring transducer,especially in such a manner, that the two coupling elements 24 ₃, 24 ₄are, as a result, arranged symmetrically to a shared imaginary crosssectional plane, in each case, cutting centrally through the fourmeasuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄. Additionally, according to afurther embodiment of the invention, the four coupling element 24 ₁, 24₂, 24 ₃, 24 ₄ of first type are so arranged in the measuring transducer,that the distance of the center of mass of the third coupling element 24₃ of first type from the center of mass of the measuring transducer isgreater than the distance of the center of mass of the first couplingelement 24 ₁ of first type from said center of mass of the measuringtransducer and greater than the distance of the center of mass of thesecond coupling element 24 ₂ of first type from said center of mass ofthe measuring transducer.

As directly evident from the combination of FIGS. 4, 5 a and 5 b, aminimum separation between the coupling element of first type affixed onthe inlet side to a particular measuring tube and lying nearest to thecenter of mass of the measuring transducer 11—here thus the firstcoupling element 24 ₁ of first type—, and the coupling element of firsttype affixed on the outlet side to said measuring tube and lying nearestto the center of mass of the measuring transducer—here thus the secondcoupling element 24 ₂ of first type—, defines, in each case, a free,oscillatory length, L_(18x), of such measuring tube, wherein, accordingto an additional embodiment of the invention, the coupling elements offirst type are so placed in the measuring transducer, that, as a result,the free, oscillatory length of each of the measuring tubes 18 ₁, 18 ₂,18 ₃, 18 ₄ amounts to less than 2500 mm, especially less than 2000 mmand/or more than 800 mm. Alternatively or in supplementation, it isadditionally provided, that all four measuring tubes 18 ₁, 18 ₂, 18 ₃,18 ₄ have the same, free, oscillatory length L_(18x).

It can additionally, in the context of a still simpler and yet moreexact adjusting of the oscillatory behavior of the measuring transducer,be quite of advantage, when the measuring transducer, such as, forexample, provided in US-A 2006/0150750, moreover, has still othercoupling elements of the aforementioned type serving for forming inlet,or outlet, side, oscillation nodes for vibrations, especially bendingoscillations, of the first measuring tube and for thereto opposite phasevibrations, especially bending oscillations, of the second measuringtube, or for vibrations, especially bending oscillations, of the thirdmeasuring tube and for thereto opposite phase vibrations, especiallybending oscillations, of the fourth measuring tube, for example, thus,in total, 6 or 8 such coupling elements of first type.

For creation of an as compact as possible measuring transducer ofsufficiently high oscillation quality factor and high sensitivity in thecase of as little pressure drop as possible, according to an additionalembodiment of the invention, the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄are so dimensioned relative to the mentioned free, oscillatory lengththat a caliber to oscillatory length ratio D₁₈/L_(18x) of the measuringtransducer, as defined by a ratio of the caliber D₁₈ of the firstmeasuring tube to the free, oscillatory length L_(18x) of the firstmeasuring tube, amounts to more than 0.07, especially more than 0.09and/or less than 0.15. Alternatively or in supplementation, for this,according to an additional embodiment of the invention, the measuringtubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are so dimensioned relative to the abovementioned installed length L₁₁ of the measuring transducer that anoscillatory length to installed length ratio L_(18x)/L₁₁ of themeasuring transducer, as defined by a ratio of the free, oscillatorylength L_(18x) of the first measuring tube to the installed length L₁₁of the measuring transducer, amounts to more than 0.55, especially morethan 0.6 and/or less than 0.9.

According to an additional embodiment of the invention, the oscillationsensors, relative to the free, oscillatory length, are so arranged inthe measuring transducer, that a measuring length to oscillatory lengthratio of the measuring transducer, as defined by a ratio of thementioned measuring length of the measuring transducer to the free,oscillatory length of the first measuring tube, amounts to more than0.6, especially more than 0.65 and/or less than 0.95.

For creation of an as compact as possible measuring transducer, whichis, nevertheless, however, as sensitive as possible to mass flow,according to an additional embodiment of the invention, the oscillationsensors are so arranged in the measuring transducer relative to theinstalled length of the measuring transducer that a measuring length toinstalled length ratio of the measuring transducer, which is defined bya ratio of the measuring length to the installed length of the measuringtransducer, amounts to more than 0.3, especially more than 0.4 and/orless than 0.7. Alternatively or in supplementation, the oscillationsensors are, according to an additional embodiment of the invention, soplaced in the measuring transducer relative to the measuring tubes, thata caliber to measuring length ratio D₁₈/L₁₉ of the measuring transducer,which is defined by a ratio of the caliber D₁₈ of the first measuringtube to the measuring length L₁₉ of the measuring transducer, amounts tomore than 0.05, especially more than 0.09. In an additional embodimentof the invention, additionally, the above mentioned measuring length L₁₉is kept smaller than 1200 mm.

In an additional embodiment of the invention, it is further providedthat the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are driven, duringoperation, pairwise synchronously, thus with equal phase position, sothat the oscillations of all four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄are only pairwise out of phase. In advantageous manner, the oscillatorybehavior of the inner part formed by means of the four measuring tubes18 ₁, 18 ₂, 18 ₃, 18 ₄, together with the exciter mechanism, and thesensor arrangement, as well as also the driver signals controlling theexciter mechanism, are so matched to one another, that at least theoscillations of the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ excitedin the wanted mode are so developed, that the first and the secondmeasuring tubes 18 ₁, 18 ₂ oscillate with essentially opposite phaserelative to one another, thus with an opposing phase shift of about180°, and also the third and fourth measuring tubes 18 ₃, 18 ₄ oscillatewith essentially opposite phase relative to one another, while,simultaneously, the first and third measuring tubes 18 ₁, 18 ₃ oscillatewith essentially equal phase relative to one another and the second andfourth measuring tubes 18 ₂, 18 ₄ oscillate with essentially equal phaserelative to one another.

Therefore, the measuring transducer includes, according to a furtherembodiment of the invention, additionally a first coupling element 25 ₁of second type, especially a plate shaped or rod shaped, first couplingelement 25 ₁ of second type, which is affixed to the first measuringtube 18 ₁ and to the third measuring tube 18 ₃, but, otherwise, to noother measuring tube, thus only to the first measuring tube 18 ₁ and tothe third measuring tube 18 ₃, and spaced both from the first couplingelement 24 ₁ of first type as well as also from the second couplingelement 24 ₂ of first type, for synchronizing vibrations, especiallybending oscillations, of the first measuring tube 18 ₁ and thereto equalfrequency vibrations, especially bending oscillations, of the thirdmeasuring tube 18 ₃. Furthermore, the measuring transducer comprises, atleast in the case of this embodiment of the invention, at least a secondcoupling element 25 ₂ of second type, especially a plate shaped or rodshaped, second coupling element 25 ₂ of second type, which is affixed tothe second measuring tube 18 ₂ and to the fourth measuring tube 18 ₄,but otherwise to no other measuring tube, thus only to the secondmeasuring tube 18 ₂ and to the fourth measuring tube 18 ₄, and spacedboth from the first coupling element 24 ₁ of first type as well as alsofrom the second coupling element 24 ₁ of first type, as well as alsofrom the first coupling element 25 ₁ of second type, for synchronizingvibrations, especially bending oscillations, of the second measuringtube 18 ₂ and thereto equal frequency vibrations, especially bendingoscillations, of the fourth measuring tube 18 ₄. As directly evidentfrom the combination of FIGS. 4, 5 a and 5 b, the first and secondcoupling elements 25 ₁, 25 ₂ of second type are placed in the measuringtransducer 11 as oppositely lying to one another as possible.

An advantage of the mechanical coupling of the measuring tubes in theabove described manner is, among other things, to be seen in the factthat the four measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ are reduced to twomeasuring tube composites acting, in each case, effectively as oneoscillatory system, each thus acting essentially as a single measuringtube, since the exciter forces produced by the exciter mechanism 5 act,due to the mechanical coupling, both between the first and secondmeasuring tubes 18 ₁, 18 ₂ as well as also equally between the third andfourth measuring tubes 18 ₃, 18 ₄, and, in turn, also the reactionforces caused in the through-flowing media for purposes of the measuringare transmitted, in each case, together back to the oscillation sensorsof the sensor arrangement 5. Furthermore, possible differences betweenthe individual measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄ can as regardstheir nominal oscillatory behavior, e.g. as a result of non-uniformflow, different temperatures, and/or different density distributions,etc., be cancelled in very simple manner. The application of couplingelements of second type has additionally also the advantage, that eachof the two measuring tube composites formed, thus, in very simplemanner, acts, not only for the exciter mechanism, but equally also forthe sensor arrangement 19, and, thus, also for the measuring, andoperating, circuit of the measuring device electronics 12, in total,practically, in each case, as a single measuring tube, and the measuringtransducer 11, thus, from the point of view of the measuring, andoperating, circuit, seems to have only two measuring tubes oscillatingrelative to one another. As a result of this, at least for thepreprocessing and possible digitizing of the oscillation measurementsignals, proven signal processing technologies and also proven,especially two channel (thus processing oscillation measurement signalsdelivered from only two oscillation sensors) measuring circuits from thefield of Coriolis, mass flow, or density measurement, can be utilized.Equally, thus, also for the operating circuit driving the excitermechanism, driver circuits known to those skilled in the art, especiallysuch operating on one channel, thus delivering exactly one driver signalfor the exciter mechanism, can be directly used. In case required,however, also the oscillation measurement signals delivered, in eachcase, from the two or more oscillation sensors can, however, also beindividually preprocessed and correspondingly digitized in, in eachcase, separate measuring channels; equally, in case required, also the,in given cases, present, two or more oscillation exciters can beoperated separately by means of separate driver signals.

According to an embodiment of the invention, the measuring tubes 18 ₁,18 ₂, 18 ₃, 18 ₄, as well as the coupling elements connecting these withone another, are, consequently, additionally so formed and somechanically coupled with one another by means of coupling elements ofsecond type, in given cases, supplementally also by means of couplingelements of first type, that a first measuring tube composite formedfrom the first and the third measuring tubes 18 ₁, 18 ₃ and a secondmeasuring tube composite formed by the second and the fourth measuringtubes 18 ₂, 18 ₄ have essentially the same mechanical eigenfrequencies.

In the example of an embodiment shown here, the first coupling element25 ₁ of second type is affixed to the first and third, measuring tubes18 ₁, 18 ₃, respectively, in the region of 50% of a minimum separationbetween the first coupling element 24 ₁ of first type and the secondcoupling element 24 ₂ of first type—, as a result, thus at about halfthe free, oscillatory length of the first and third measuring tubes 18₁, 18 ₃, respectively. Additionally, also the second coupling element ofsecond type is in corresponding manner affixed to the second and fourthmeasuring tubes 18 ₂, 18 ₄, respectively, in the region of 50% of aminimum separation between the first coupling element 24 ₁ of first typeand the second coupling element 24 ₂ of first type, thus at about halfthe free, oscillatory length of the second and fourth measuring tubes 18₂, 18 ₄, respectively.

In advantageous manner, the coupling elements of second type cansupplementally also serve as holders of components of the excitermechanism 5. Therefore, according to an additional embodiment of theinvention, it is provided, that each of the oscillation exciters 5 ₁, 5₂, especially equally constructed oscillation exciters, is held,partially, in each case, on two coupling elements of second type—here,the first and second coupling elements 25 ₁, 25 ₂—lying opposite to oneanother. Thus, it can, in very effective and, equally as well, verysimple manner, be assured, that the exciter force generated by means ofthe oscillation exciter 5 ₁ effects at least predominantly synchronous,especially also of essentially equal phase to one another, bendingoscillations of the first and third measuring tubes 18 ₁, 18 ₃, or thesecond and fourth measuring tubes 18 ₂, 18 ₄. For example, in the caseof electrodynamic oscillation exciters, the cylindrical coil can beaffixed to the first coupling element of second type and the, in eachcase, associated permanent magnet to the oppositely lying, secondcoupling element of second type. For the mentioned case, in which theexciter mechanism 5 has two oscillation exciters 5 ₁, 5 ₂ both the firstoscillation exciter 5 ₁ as well as also the second oscillation exciter 5₂ can, in each case, be held on the first and second coupling elements25 ₁, 25 ₂ of second type, for example, also in such a manner, that, asdirectly evident from FIG. 4, or FIG. 5 a, there is a minimum separationbetween the first and second oscillation exciters 5 ₁, 5 ₂ of more thantwice as large as a tube outer diameter of the measuring tubes 18 ₁, 18₂, 18 ₃, 18 ₄, at least, however, of the first measuring tube 18 ₁. Inthis way, in total, an optimal exploitation of the available room in theinner space of the transducer housing 7 ₁ is enabled, as well as also asimple mounting of the oscillation exciters 5 ₁, 5 ₂.

According to an additional embodiment of the invention, the measuringtransducer comprises, additionally, a third coupling element 25 ₃ ofsecond type, for example, again, a plate shaped or rod shaped, couplingelement of second type, which is affixed to the first measuring tube 18₁ and to the third measuring tube 18 ₃, but otherwise to no othermeasuring tube, thus only to the first measuring tube 18 ₁ and to thethird measuring tube 18 ₃, and spaced both from the first couplingelement 24 ₁ of first type as well as also from the second couplingelement 24 ₂ of first type, as well as also from the first couplingelement 25 ₁ of second type, for synchronizing vibrations, especiallybending oscillations, of the first measuring tube 18 ₁ and thereto equalfrequency vibrations, especially bending oscillations, of the thirdmeasuring tube 18 ₃, as well as a fourth coupling element 25 ₄ of secondtype, especially a plate shaped or rod shaped, coupling element ofsecond type, which is affixed to the second measuring tube 18 ₂ and tothe fourth measuring tube 18 ₄, but otherwise to no other measuringtube, thus only to the second measuring tube 18 ₂ and to the fourthmeasuring tube 18 ₄, and spaced both from the first and second couplingelements of first type as well as also from the second and thirdcoupling elements of second type, in each case, for synchronizingvibrations, especially bending oscillations, of the second measuringtube 18 ₂ and thereto equal frequency vibrations, especially bendingoscillations, of the fourth measuring tube 18 ₄. The third and fourthcoupling elements 25 ₃, 25 ₄ of second type are, such as directlyevident from the combination of FIGS. 4, 5 a and 5 b, preferably placedin the measuring transducer 11 lying opposite to one another.

Additionally, the measuring transducer 11 comprises, according to anadditional embodiment of the invention, a fifth coupling element 25 ₅ ofsecond type, especially a plate shaped or rod shaped fifth couplingelement 25 ₅ of second type, which is affixed to the first measuringtube 18 ₁ and to the third measuring tube 18 ₃, but otherwise to noother measuring tube, thus only to the first measuring tube 18 ₁ and tothe third measuring tube 18 ₃, and spaced both from the first and secondcoupling elements of first type as well as also from the first and thirdcoupling elements of second type, for synchronizing vibrations,especially bending oscillations, of the first measuring tube 18 ₁ and ofthereto equal frequency vibrations, especially bending oscillations, ofthe third measuring tube 18 ₃, as well as a sixth coupling element 25 ₆of second type, especially a plate shaped or rod shaped, sixth couplingelement 25 ₆ of second type, which is affixed to the second measuringtube 18 ₂ and to the fourth measuring tube 18 ₄, but otherwise to noother measuring tube, thus only to the second measuring tube 18 ₂ and tothe fourth measuring tube 18 ₄, and spaced, in each case, both from thefirst and second coupling elements of first type as well as also fromthe second, fourth and fifth coupling elements of second type, forsynchronizing vibrations, especially bending oscillations, of the secondmeasuring tube and of thereto equal frequency vibrations, especiallybending oscillations, of the fourth measuring tube. The fifth and sixthcoupling elements 25 ₅, 25 ₆ of second type are, preferably, again,placed lying opposite to one another in the measuring transducer 11.

Furthermore, it can be of advantage to use the aforementioned couplingelements of second type additionally also for holding individualcomponents of the sensor arrangement. In accordance therewith, it isprovided, according to an additional embodiment of the invention, thatthe inlet-side, first oscillation sensor 19 ₁ is held, partially, ineach case, on the third and fourth coupling elements 25 ₃, 25 ₄ ofsecond type. Additionally, the second oscillation sensor 19 ₂ is, incorresponding manner, held on the fifth and sixth coupling elements 25₅, 25 ₆ of second type. Thus, it can, in very effective, equally as wellvery simple manner, be assured, that the oscillation measurement signalgenerated, during operation, by means of the first oscillation sensor 19₁ represents. at least predominantly, synchronous, inlet-side, bendingoscillations (especially also bending oscillations of equal phase to oneanother) of the first and third measuring tubes 18 ₁, 18 ₃ relative tothe equally synchronized, inlet-side, bending oscillations (especiallyalso bending oscillations of phase equal to one another) of the secondand fourth measuring tubes 18 ₂, 18 ₄, or that the oscillationmeasurement signal generated, during operation, by means of the secondoscillation sensor 19 ₂ represents, at least predominantly, synchronous,outlet-side, bending oscillations (especially also bending oscillationsof phase equal to one another) of the first and third measuring tubes 18₁, 18 ₃ relative to the equally synchronized, outlet-side, bendingoscillations (especially also bending oscillations of phase equal to oneanother) of the second and fourth measuring tubes 18 ₂, 18 ₄. Forexample, in the case of electrodynamic oscillation sensors, thecylindrical coil of the first oscillation sensor 19 ₁ can be affixed tothe third coupling element of second type and the associated permanentmagnet to the oppositely lying, fourth coupling element of second type,or the cylindrical coil of the second oscillation sensor 19 ₂ can beaffixed to the fifth, and the associated permanent magnet to theoppositely lying, sixth coupling element of second type. For thementioned case, in which the sensor arrangement 19 is formed by means offour oscillation sensors 19 ₁, 19 ₂, 19 ₃, 19 ₄, according to anadditional embodiment of the invention, both the first oscillationsensor 19 ₁ as well as also the third oscillation sensor 19 ₃ are, ineach case, partially held on the third and fourth coupling elements ofsecond type, especially in such a manner, that, such as directly evidentfrom the combination of FIGS. 4, 5 a and 5 b, a minimum separationbetween the first and third oscillation sensors 19 ₁, 19 ₃ is more thantwice as large as a tube outer diameter of the first measuring tube 18₁. In corresponding manner, additionally, also the second oscillationsensor 19 ₂ and the fourth oscillation sensor 19 ₄ can, in each case, beheld on the fifth and sixth coupling elements of second type, especiallyin such a manner, that, as directly evident from the combination ofFIGS. 4, 5 a and 5 b, a minimum separation between the second and fourthoscillation sensors 19 ₂, 19 ₄ is more than twice as large as a tubeouter diameter of the first measuring tube 18 ₁, whereby, in total, anoptimal exploitation of the room available in the inner space of thetransducer housing 7 ₁, as well as also a simple mounting of theoscillation sensors of the sensor arrangement 19, is enabled. Therefore,according to an additional embodiment of the invention, each of theoscillation sensors, especially equally constructed oscillation sensors,of the sensor arrangement 19 is held on two coupling elements of secondtype lying opposite to one another.

For additional improvement of the oscillation quality factor of theinner part in the case of an as short installed length L₁₁ of themeasuring transducer 11 as possible, or an as short free, oscillatorylength L_(18x) of the measuring tubes 18 ₁, 18 ₂, 18 ₃, or 18 ₄ aspossible, the measuring transducer comprises, according to an additionalembodiment of the invention, a plurality of annular stiffening elements22 _(1A), . . . 22 _(2A), . . . 22 _(3A), . . . 22 _(4A), . . . ,especially annular stiffening elements constructed equally to oneanother. Each of these stiffening elements is so placed on exactly oneof the measuring tubes 18 ₁, 18 ₂, 18 ₃, 18 ₄, that it grips around itstube along an imaginary peripheral line thereof, especially a circularlyorbiting, peripheral line; compare, in this connection, also theinitially mentioned U.S. Pat. No. 6,920,798. Especially, in such case,it is, additionally provided, that at least four of said stiffeningelements 22 _(1A), 22 _(1B), 22 _(1C), 22 _(1D), or 22 _(2A), 22 _(2B),22 _(2C), 22 _(2D), or 22 _(3A), 22 _(3B), 22 _(3C), 22 _(3D), or 22_(4A), 22 _(4B), 22 _(4C), 22 _(4D), especially equally constructedstiffening elements, are placed on each of the measuring tubes 18 ₁, 18₂, 18 ₃, and 18 ₄, respectively. The stiffening elements 22 _(1A), . . .22 _(3A), . . . 22 _(4A), . . . are, in advantageous manner, so placedin the measuring transducer 11, that two adjoining stiffening elementsmounted on the same measuring tube have, relative to one another aseparation, which amounts to at least 70% of a tube outer diameter ofsaid measuring tube, at most, however, 150% of such tube outer diameter.Found as especially suitable has been, in such case, a separation ofneighboring stiffening elements relative to one another, which lies inthe range of 80% to 120% of the tube outer diameter of the respectivemeasuring tube 18 ₁, 18 ₂, 18 ₃, and 18 ₄, respectively. Alternativelythereto or in supplementation thereof, for improving the oscillationproperties of the inner part and; thus, also for improving the measuringaccuracy of the measuring transducer, it is additionally provided thatthe measuring transducer, such as shown schematically in FIGS. 7, 8 a, 8b, additionally has plate-shaped stiffening elements 26 ₁, 26 ₂, 26 ₃,26 ₄ for tuning the natural eigenfrequencies of bending oscillations ofthe measuring tubes 18 ₁, 18 ₂, 18 ₃, and 18 ₄, respectively, also inthose planes of oscillation YZ₁, YZ₂, which, as evident in conjunctionwith the FIGS. 3 a, 3 b, are essentially perpendicular to the abovementioned planes of oscillation XZ₁, XZ₂. The, for example, equallyconstructed, plate-shaped stiffening elements 26 ₁, 26 ₂, 26 ₃, 26 ₄are, in such case, especially so embodied and, in each case, soconnected with the measuring tubes, that, as a result, at least thebending oscillation resonance frequencies of the bending oscillations ofthe measuring tubes 18 ₁, 18 ₂, 18 ₃, and 18 ₄, respectively, excited inthe wanted mode in the aforementioned—primary—planes of oscillation XZ₁,XZ₂ are always lower than the natural eigenfrequencies of bendingoscillations of the measuring tubes, which are of equal modal order asthe wanted mode, but were executed within the—thus, secondary—planes ofoscillation YZ₁, YZ₂. In this way, in very simple, yet very effectivemanner as regards the respective resonance frequencies of the measuringtubes, a significant separation of the bending oscillation modes of themeasuring tubes in the mutually perpendicular—here, primary andsecondary—planes of oscillation of the inner part, or of the measuringtubes, can be achieved.

For this purpose, the measuring transducer, in a further embodiment ofthe invention directly evident from the combination of FIGS. 7, 8 a, 8b, has a first plate-shaped stiffening element 26 ₁, which, for tuningone or more resonance frequencies of bending oscillations of the firstmeasuring tube 18 ₁ and of the third measuring tube 18 ₃ ina—secondary—third plane of oscillation YZ₁ in each case essentiallyperpendicular to the—primary—planes of oscillation XZ₁, XZ₂, is affixedto the first measuring tube 18 ₁ and to the third measuring tube 18 ₃,and, indeed, in each case, to a segment 18′₁, 18′₂ of the first andthird measuring tubes 18 ₁, 18 ₃, respectively, lying between the firstoscillation exciter 5 ₁ and the first flow divider 20 ₁.

Further, the measuring transducer in this embodiment of the inventionincludes a second plate-shaped stiffening element 26 ₂, which, fortuning one or more resonance frequencies of bending oscillations of thesecond measuring tube 18 ₂ and of the fourth measuring tube 18 ₄ ina—secondary—fourth plane of oscillation YZ₂, in each case, essentiallyperpendicular to the—primary—planes of oscillation XZ₁, XZ₂, as well asalso essentially parallel to the aforementioned third plane ofoscillation YZ₁, is affixed to the second measuring tube 18 ₂ and to thefourth measuring tube 18 ₄, namely, in each case, to a segment 18′₂,18′₄ of the second and fourth measuring tubes 18 ₂, 18 ₄, respectively,lying between the first oscillation exciter 5 ₁ and the first flowdivider 20 ₁.

Moreover, the measuring transducer includes a third plate-shapedstiffening element 26 ₃, which, for tuning said resonance frequencies ofbending oscillations of the first measuring tube 18 ₁ and of the thirdmeasuring tube 18 ₃ in the third plane of oscillation YZ₁, is affixed tothe first measuring tube 18 ₁ and to the third measuring tube 18 ₃—here,in each case, to a segment 18″₁, 18″₃ of the first and third measuringtubes 18 ₁, 18 ₃, respectively, lying between the first oscillationexciter 5 ₁ and the second flow divider 20 ₂; as well as a fourthplate-shaped stiffening element 26 ₄, which, for tuning said resonancefrequencies of bending oscillations of the second measuring tube 18 ₂and of the fourth measuring tube 18 ₄ in the fourth plane of oscillationYZ₂, is affixed to the second measuring tube 18 ₂ and to the fourthmeasuring tube 18 ₄—here, in each case, to a segment 18″₂, 18″₄ of thesecond and fourth measuring tubes 18 ₁, 18 ₄, respectively lying betweenthe first oscillation exciter 5 ₁ and the second flow divider 20 ₂. Forexample, in this case, the first and second plate-shaped stiffeningelements 26 ₁, 26 ₂ can, in each case, be placed between the firstoscillation sensor 19 ₁ and the first flow divider 20 ₁, especially alsobetween the above mentioned first and third coupling elements 24 ₁, 24 ₃of first type, while the third and fourth plate-shaped stiffeningelements 26 ₃, 26 ₄ can, in each case, be placed between the secondoscillation sensor 19 ₂ and the second flow divider 20 ₂, especiallyalso between the above mentioned second and fourth coupling elements 24₂, 24 ₄ of first kind. The plate-shaped stiffening elements can, forexample, however, also be so arranged in the measuring transducer, that,as also evident from the combination of FIGS. 7, 8 a, 8 b, the first andsecond plate-shaped stiffening elements 26 ₁, 26 ₂ are, in each case,placed between the first coupling element 24 ₁ of first type and thefirst oscillation sensor 19 ₁; and the third and fourth plate-shapedstiffening elements 26 ₃, 26 ₄ are, in each case, placed between thesecond coupling element 24 ₂ of first type and the second oscillationsensor 19 ₂.

The plate-shaped stiffening elements can be connected by soldering,brazing or welding with the respective measuring tubes. For example, thestiffening elements can, in such case, be connected with the measuringtubes in a manner such that, as also evident from the combination ofFIGS. 7, 8 a, 8 b, the first plate-shaped stiffening element 26 ₁ isaffixed to the segment 18′₁ of the first measuring tube 18 ₁ lyingbetween the first oscillation sensor 19 ₁ and the first flow divider 20₁ along one of the straight lateral surface elements, of thesegment—here, for instance, the one lying nearest to the third measuringtube 18 ₃—as well as to the segment 18′₃ of the third measuring tube 18₃ lying, as well, between the first oscillation sensor 19 ₁ and thefirst flow divider 20 ₁ along a straight lateral surface elementthereof—here, for instance, that lying nearest to the first measuringtube. In analogous manner thereto, then also the second plate-shapedstiffening element 26 ₂ is affixed to the segments 18′₂ and 18′₄,respectively, of the second and fourth measuring tubes 18 ₂, 18 ₄,lying, in each case, between the first oscillation sensor 19 ₁ and thefirst flow divider 20 ₁, the third plate-shaped stiffening element 26 ₃is affixed to the segments 18″₁ and 18″₃, respectively, of the first andthird measuring tubes 18 ₁, 18 ₃, lying, in each case, between thesecond oscillation sensor 19 ₂ and the second flow divider 20 ₂, and thefourth plate-shaped stiffening element 26 ₄ is affixed to the segments18″₂ and 18″₄, respectively, of the second and fourth measuring tubes 18₂, 18 ₄, lying, in each case, between the second oscillation sensor 19 ₂and the second flow divider 20 ₂, and, indeed, in each case, along oneof the straight lateral surface elements of the respective measuringtube. For achieving a sufficient separation of the resonancefrequencies, each of the four plate-shaped stiffening elements 26 ₁, 26₂, 26 ₃, 26 ₄, according to a further embodiment of the invention, is soembodied and so placed in the measuring transducer that it has a heightcorresponding to a smallest separation between the lateral surfaceelements of those two measuring tubes 18 ₁, 18 ₃ and 18 ₂, 18 ₄, alongwhich it is, in each case, affixed, which height is smaller than alength of the respective plate-shaped stiffening element 26 ₁, 26 ₂, 26₃, 26 ₄ measured in the direction of said lateral surface elements, forexample in such a manner that the height is less than 50%, especiallyless than 30%, of said length. Additionally, it is of advantage, wheneach of the four plate-shaped stiffening elements 26 ₁, 26 ₂, 26 ₃, 26 ₄is additionally, in each case, so embodied that the length of each ofthe plate-shaped stiffening elements is greater, for example more thantwo times, especially more than 5 times an associated breadth of thesaid plate-shaped stiffening element 26 ₁, 26 ₂, 26 ₃, 26 ₄ measuredtransversely to length and height. Alternatively to the affixing to the,in each case, nearest lateral surface elements, the stiffening elementscan, however, also, for example, be so embodied and so connected withthe measuring tubes, especially also while keeping the aforementionedheight to breadth to length relationships, that each of the stiffeningelements essentially tangentially contacts the respective two measuringtubes, for example, in each case, along the lateral surface element ofeach of the measuring tubes lying farthest outwards or farthest inwards.

Through the application of four instead of, such as to this point, twomeasuring tubes flowed-through in parallel, it is then also possible tomanufacture, cost effectively, measuring transducers of the describedtype also for large mass flow rates, or with large nominal diameters offar over 250 mm, on the one hand, with an accuracy of measurement ofover 99.8% at an acceptable pressure drop, especially of about 1 bar orless, and, on the other hand, to keep the installed mass, as well asalso the empty mass, of such measuring transducers sufficiently inlimits, that, in spite of large nominal diameter, manufacture,transport, installation, as well as also operation can always stilloccur economically sensibly. Especially also through implementing ofabove explained measures for further developing theinvention—individually or also in combination—, measuring transducers ofthe type being discussed can also, in the case of large nominaldiameter, be so embodied and so dimensioned, that a mass ratio of themeasuring transducer, as defined by a ratio of the mentioned empty massof the measuring transducer to a total mass of the inner part formed bymeans of the four measuring tubes and the thereto held excitermechanism, and sensor arrangement, as well as, in given cases,components of the measuring transducer affixed additionally to themeasuring tubes and influencing their oscillatory behavior, can be keptdirectly smaller than 3, especially smaller than 2.5.

1. A measuring transducer of the vibration-type for registering at leastone physical, measured variable of a flowable medium guided in apipeline and/or for producing Coriolis forces serving for registering amass flow rate of a flowable medium, said measuring transducercomprising a transducer housing with an inlet-side first housing endformed by means of an inlet-side a first flow divider, and with anoutlet-side second housing end formed by means of an outlet-side secondflow divider, said first flow divider including four, mutually spaced,flow openings and said first flow divider including a flange forconnecting the measuring transducer to a tubular segment of the pipelineserving for supplying medium to the measuring transducer, said secondflow divider including four, mutually spaced, flow openings and saidsecond flow divider including a flange for connecting the measuringtransducer to a tubular segment of the pipeline serving for removingmedium from the measuring transducer, and each of said flangesincluding, respectively, a sealing surface for fluid tight connecting ofthe measuring transducer with the corresponding tubular segment of thepipeline; said measuring transducer further comprising four, straight,measuring tubes, which are connected to the flow dividers for guidingflowing medium along flow paths connected in parallel, of whichmeasuring tubes, a first measuring tube, opens with an inlet-side, firstmeasuring tube end into a first flow opening of the first flow dividerand with an outlet-side, second measuring tube end into a first flowopening of the second flow divider, a second measuring tube, opens withan inlet-side, first measuring tube end into a second flow opening ofthe first flow divider and with an outlet-side, second measuring tubeend into a second flow opening of the second flow divider, a thirdmeasuring tube, opens with an inlet-side, first measuring tube end intoa third flow opening of the first flow divider and with an outlet-side,second measuring tube end into a third flow opening of the second flowdivider, and a fourth measuring tube, opens with an inlet-side, firstmeasuring tube end into a fourth flow opening of the first flow dividerand with an outlet-side, second measuring tube end into a fourth flowopening of the second flow divider, and said measuring transducerfurther comprising an electromechanical exciter mechanism for producingand/or maintaining mechanical oscillations of said four measuring tubes,said exciter mechanism being adapted to excite said first measuring tubeand said second measuring tube to execute opposite phase bendingoscillations in a shared imaginary first plane of oscillation and toexcite said third measuring tube and said fourth measuring tube toexecute opposite phase bending oscillations in a shared imaginary,second plane of oscillation; wherein: a nominal diameter, D₁₁, of themeasuring transducer, which corresponds to a caliber of the pipeline, inwhose course the measuring transducer is to be used, amounts to morethan 100 mm, and a distance between the sealing surfaces of both flangesdefines an installed length, L₁₁, of the measuring transducer amountingto more than 1200 mm.
 2. The measuring transducer as claimed in claim 1,wherein: each of the two flanges has a mass of more than 50 kg.
 3. Themeasuring transducer as claimed in claim 1, wherein: a nominal diameter,D₁₁, of the measuring transducer, which corresponds to a caliber of thepipeline, in whose course the measuring transducer is to be used,amounts to more than 300 mm.
 4. The measuring transducer as claimed inclaim 1, wherein: said transducer housing is embodied essentiallytubularly and/or circularly cylindrically.
 5. The measuring transduceras claimed in claim 4, wherein: said transducer housing shows a largesthousing inner diameter, D₇, which is greater than 150 mm.
 6. Themeasuring transducer as claimed in claim 5, wherein: a housing tomeasuring tube, inner diameter ratio, D₇/D₁₈, the measuring transducer,as defined by a ratio of the largest housing inner diameter, D₇, to acaliber, D₁₈, of the first measuring tube is greater than
 3. 7. Themeasuring transducer as claimed in claim 5, wherein: a housing innerdiameter to nominal diameter ratio, D₇/D₁₁, of the measuring transducer,as defined by a ratio of the largest housing inner diameter, D₇, to thenominal diameter, D₁₁, of the measuring transducer is smaller than 1.5.8. The measuring transducer as claimed in claim 1, wherein: an emptymass, M₁₁, of the measuring transducer is greater than 200 kg.
 9. Themeasuring transducer as claimed in claim 8, wherein: a mass to nominaldiameter ratio, M₁₁/D₁₁, of the measuring transducer, as defined by aratio of the empty mass, M₁₁, of the measuring transducer to the nominaldiameter, D₁₁, of the measuring transducer, is smaller than 2 kg/mm. 10.The measuring transducer as claimed in claim 1, wherein: a nominaldiameter to installed a length ratio, D₁₁/L₁₁, of the measuringtransducer, as defined by a ratio of the nominal diameter of themeasuring transducer to the installed length of the measuringtransducer, is smaller than 0.3.
 11. A measuring transducer as claimedin claim 10, wherein: the nominal diameter to installed length ratio,D₁₁/L₁₁, of the measuring transducer is smaller than 0.2, and/or thenominal diameter to installed length ratio, D₁₁/L₁₁, of the measuringtransducer is greater than 0.1.
 12. The measuring transducer as claimedin claim 1, further comprising: a first coupling element of first type,which is affixed on the inlet side at least to the first measuring tubeand to the second measuring tube and spaced both from the first flowdivider as well as also from the second flow divider, for forminginlet-side, oscillation nodes at least for vibrations, especiallybending oscillations, of the first measuring tube and for theretoopposite phase vibrations, especially bending oscillations, of thesecond measuring tube; and a second coupling element of first type,which is affixed on the outlet side at least to the first measuring tubeand to the second measuring tube and spaced both from the first flowdivider as well as also from the second flow divider, as well as alsofrom the first coupling element, for forming outlet-side, oscillationnodes at least for vibrations of the first measuring tube and forthereto opposite phase vibrations of the second measuring tube.
 13. Themeasuring transducer as claimed in claim 12, wherein: said firstcoupling element of the first type is affixed also to the thirdmeasuring tube and to the fourth measuring tube, and said secondcoupling element of the first type is affixed to the third measuringtube and to the fourth measuring tube; and/or a center of mass of saidfirst coupling element of the first type has a distance to a center ofmass of the measuring transducer, which is essentially equal to adistance of a center of mass of the second coupling element of firsttype to said center of mass of the measuring transducer.
 14. Themeasuring transducer as claimed in claim 12, further comprising: a thirdcoupling element of the first type, said third coupling element of thefirst type, which is affixed on the inlet side at least to said thirdmeasuring tube and to said fourth measuring tube and spaced both fromsaid first flow divider as well as also from said second flow divider,for forming inlet-side, oscillation nodes at least for vibrations ofsaid third measuring tube and for thereto opposite phase vibrations ofsaid fourth measuring tube, and a fourth coupling element of the firsttype, a fourth coupling element of the first type, which is affixed onthe outlet side at least to said third measuring tube and to said fourthmeasuring tube and spaced both from said first flow divider as well asalso from said second flow divider, as well as also from said thirdcoupling element of the first type, for forming outlet-side, oscillationnodes at least for vibrations of said third measuring tube and forthereto opposite phase vibrations of the fourth measuring tube.
 15. Themeasuring transducer as claimed in claim 14, wherein: said thirdcoupling element of the first type is affixed both to said firstmeasuring tube as well as also to said second measuring tube and spaced,in each case, from said first and said second coupling elements of thefirst type, and said fourth coupling element of the first type isaffixed both to said first measuring tube as well as also to said secondmeasuring tube and spaced, in each case, from said first and said secondcoupling elements of the first type; and/or a center of mass of saidthird coupling element of the first type has a distance to a center ofmass of the measuring transducer, which is essentially equal to adistance of a center of mass of said fourth coupling element of thefirst type to said center of mass of the measuring transducer,especially in such a manner that the distance of the center of mass ofsaid third coupling element of the first type from the center of mass ofthe measuring transducer is greater than a distance of the center ofmass of said first coupling element of the first type from said centerof mass of the measuring transducer and greater than a distance of thecenter of mass of said second coupling element of the first type fromsaid center of mass of the measuring transducer.
 16. The measuringtransducer as claimed in claim 12, wherein: a free, oscillatory length,L_(18x), of said first measuring tube, corresponding to a minimumseparation between said first coupling element of the first type andsaid second coupling element of the first type, amounts to less than2500 mm.
 17. The measuring transducer as claimed in claim 16, wherein: acaliber to oscillatory length ratio, D₁₈/L_(18x), of the measuringtransducer, as defined by a ratio of the caliber, D₁₈, of said firstmeasuring tube to the free, oscillatory length, L_(18x), of said firstmeasuring tube, amounts to more than 0.07.
 18. The measuring transduceras claimed in claim 16, wherein: an oscillatory length to installedlength ratio, L_(18x)/L₁₁, of the measuring transducer, as defined by aratio of the free, oscillatory length, L_(18x), of said first measuringtube to the installed length, L₁₁, of the measuring transducer, amountsto more than 0.55.
 19. The measuring transducer as claimed in claim 16,wherein: a measuring length to oscillatory length ratio, L₁₉/L_(18x), ofthe measuring transducer, as defined by a ratio of the measuring length,L₁₉, of the measuring transducer to the free, oscillatory length,L_(18x), of said first measuring tube, amounts to more than 0.6.
 20. Themeasuring transducer as claimed in claim 16, wherein: a measuring lengthto oscillatory length ratio, L₁₉/L_(18x), of the measuring transducer,as defined by a ratio of the measuring length, L₁₉, of the measuringtransducer to the free, oscillatory length, L_(18x), of said firstmeasuring tube, amounts to more than 0.6 and less than 0.95.
 21. Themeasuring transducer as claimed in claim 12, further comprising: a firstcoupling element of the second type, which is affixed to said firstmeasuring tube and to said third measuring tube, but otherwise to noother measuring tube, and spaced both from said first coupling elementof the first type as well as also from said second coupling element ofthe first type, for synchronizing vibrations, especially bendingoscillations, of said first measuring tube and thereto equal frequencyvibrations of said third measuring tube; and a second coupling elementof the second type, which is affixed to said second measuring tube andto said fourth measuring tube, but otherwise to no other measuring tube,and spaced both from said first coupling element of the first type aswell as also from said second coupling element of the first type, aswell as also from said first coupling element of the second type, forsynchronizing vibrations of said second measuring tube and thereto equalfrequency vibrations of said fourth measuring tube.
 22. The measuringtransducer as claimed in claim 21, wherein: said first coupling elementof the second type is affixed to said first measuring tube as well as tosaid third measuring tube in the region of 50% of a minimum separationbetween said first coupling element of the first type and said secondcoupling element of the first type; and said second coupling element ofthe second type is affixed to said second measuring tube and to saidfourth measuring tube in the region of 50% of a minimum separationbetween said first coupling element of the first type and said secondcoupling element of the first type.
 23. The measuring transducer asclaimed in claim 21, further comprising: a third coupling element of thesecond type, which is affixed to said first measuring tube and to saidthird measuring tube, but otherwise to no other measuring tube, andspaced both from said first coupling element of the first type as wellas also from said second coupling element of the first type, as well asalso from said first coupling element of the second type, forsynchronizing vibrations of said first measuring tube and thereto equalfrequency vibrations of sid third measuring tube; and a fourth couplingelement of the second type, which is affixed to said second measuringtube and to said fourth measuring tube, but otherwise to no othermeasuring tube, and spaced, in each case, both from said first and saidsecond coupling elements of the first type as well as also from saidsecond and said third coupling elements of the second type, forsynchronizing vibrations of said second measuring tube and thereto equalfrequency vibrations of said fourth measuring tube.
 24. The measuringtransducer as claimed in claim 23, further comprising: a fifth couplingelement of the second type, which is affixed to said first measuringtube and to said third measuring tube, but otherwise to no othermeasuring tube, and spaced both from said first and said second couplingelements of the first type as well as also from said first and saidthird coupling elements of the second type, for synchronizing vibrationsof said first measuring tube and thereto equal frequency vibrations ofsaid third measuring tube; and a sixth coupling element of the secondtype, which is affixed to said second measuring tube and to said fourthmeasuring tube, but otherwise to no other measuring tube, and spaced, ineach case, both from said first and said second coupling elements of thefirst type as well as also from said second, fourth and fifth couplingelements of the second type, for synchronizing vibrations of said secondmeasuring tube and thereto equal frequency vibrations, especiallybending oscillations, of said fourth measuring tube.
 25. The measuringtransducer as claimed in claim 1, wherein: each of said four measuringtubes has a caliber, D₁₈, which amounts to more than 60 mm.
 26. Themeasuring transducer as claimed in claim 25, wherein: a caliber toinstalled length ratio, D₁₈/L₁₁, of the measuring transducer, as definedby a ratio of the caliber, D₁₈, of said first measuring tube to theinstalled length, L₁₁, of the measuring transducer, amounts to more than0.02.
 27. The measuring transducer as claimed in claim 25, wherein: acaliber to measuring length ratio, D₁₈/L₁₉, of the measuring transducer,as defined by a ratio of the caliber, D₁₈, of said first measuring tubeto the measuring length, L₁₉, of the measuring transducer, amounts tomore than 0.05.
 28. The measuring transducer as claimed in claim 25,wherein: a caliber to measuring length ratio, D₁₈/L₁₉, of the measuringtransducer, as defined by a ratio of the caliber, D₁₈, of said firstmeasuring tube to the measuring length, L₁₉, of the measuringtransducer, amounts to more than 0.09.
 29. The measuring transducer asclaimed in claim 1, wherein: a measuring tube length, L₁₈, of said firstmeasuring tube corresponding to a minimum separation between the firstflow opening of said first flow divider and the first flow opening ofsaid second flow divider amounts to more than 1000 mm.
 30. The measuringtransducer as claimed in claim 29, wherein: a measuring tube length toinstalled length ratio, L₁₈/L₁₁, of the measuring transducer, as definedby a ratio of the measuring tube length, L₁₈, of said first measuringtube to the installed length, L₁₁, of the measuring transducer, amountsto more than 0.7.
 31. The measuring transducer as claimed in claim 30,wherein: said measuring tube length to installed length ratio, L₁₈/L₁₁,of the measuring transducer amounts to more than 0.8, and/or saidmeasuring tube length to installed length ratio, L₁₈/L₁₁, of themeasuring transducer amounts to less than 0.95.
 32. The measuringtransducer as claimed in claim 1, further comprising: a sensorarrangement reacting to vibrations of said measuring tubes for producingoscillation measurement signals representing vibrations.
 33. Themeasuring transducer as claimed in claim 32, wherein: said sensorarrangement includes an inlet-side, first oscillation sensor and anoutlet-side, second oscillation sensor.
 34. The measuring transducer asclaimed in claim 33, wherein: said sensor arrangement includes aninlet-side, third oscillation sensor, an outlet-side, fourth oscillationsensor.
 35. The measuring transducer as claimed in claim 34, wherein:said first and third oscillation sensors are interconnected electricallyin series, in such a manner, that a combined oscillation measurementsignal represents combined inlet-side oscillations of said first andsaid third measuring tubes relative to said second and said fourthmeasuring tubes; and said second and said fourth oscillation sensors areinterconnected electrically in series, in such a manner, that a combinedoscillation measurement signal represents combined outlet-sideoscillations of said first and said third measuring tubes relative tosaid second and said fourth measuring tubes.
 36. The measuringtransducer as claimed in claim 34, wherein: said third oscillationsensor is formed by means of a permanent magnet held to said thirdmeasuring tube and a cylindrical coil held to said fourth measuring tubeand permeated by the magnetic field of the permanent magnet; said fourthoscillation sensor is formed by means of a permanent magnet held to saidthird measuring tube; and a cylindrical coil held to said fourthmeasuring tube and permeated by the magnetic field of the permanentmagnet.
 37. The measuring transducer as claimed in claim 33, wherein: ameasuring length, L₁₉, of the measuring transducer, corresponding to aminimum separation between said first oscillation sensor and said secondoscillation sensor, amounts to more than 500 mm.
 38. The measuringtransducer as claimed in claim 37, wherein: a measuring length toinstalled length ratio, L₁₉/L₁₁, of the measuring transducer, as definedby a ratio of the measuring length, L₁₉, to the installed length, L₁₁,of the measuring transducer, amounts to more than 0.3.
 39. The measuringtransducer as claimed in claim 37, wherein: a measuring length toinstalled length ratio, L₁₉/L₁₁, of the measuring transducer, as definedby a ratio of the measuring length, L₁₉, to the installed length, L₁₁,of the measuring transducer, amounts to more than 0.3 and less than 0.7.40. The measuring transducer as claimed in claim 33, wherein: ameasuring length, L₁₉, of the measuring transducer, corresponding to aminimum separation between said first oscillation sensor and said secondoscillation sensor, amounts to more than 500 mm and less than 1200 mm.41. The measuring transducer as claimed in claim 1, wherein: said fourmeasuring tubes are of equal construction as regards a material, ofwhich their tube walls are composed, and/or as regards their geometrictube dimensions.
 42. The measuring transducer as claimed in claim 1,wherein: both said third measuring tube as well as said fourth measuringtube are different from said first measuring tube and said secondmeasuring tube as regards their respective geometric tube dimensions.43. The measuring transducer as claimed in claim 1, wherein: each ofsaid measuring tubes shows a bending oscillation fundamental mode ofminimum bending oscillation, resonance frequency, f18 ₁; f18 ₂; f18 ₃;f18 ₄; said minimum bending oscillation, resonance frequencies, f18 ₁,f18 ₂, at least of said first and said second measuring tubes areessentially equal and the minimum bending oscillation, resonancefrequencies, f18 ₃, f18 ₄, at least of said third and said fourthmeasuring tubes.
 44. The measuring transducer as claimed in claim 43,wherein: the minimum bending oscillation, resonance frequencies, f18 ₁,f18 ₂, f18 ₃, f18 ₄, of all four measuring tubes are essentially equal.45. The measuring transducer as claimed in claim 43, wherein: theminimum bending oscillation, resonance frequencies, f18 ₁, f18 ₂, f18 ₃,f18 ₄, of said four measuring tubes are only pairwise equal.
 46. Themeasuring transducer as claimed in claim 1, wherein: said excitermechanism includes a first oscillation exciter, differentially excitingoscillations of said first measuring tube relative to said secondmeasuring tube.
 47. The measuring transducer as claimed in claim 46,wherein: said exciter mechanism includes a second oscillation exciter,differentially exciting oscillations of said third measuring tuberelative to said fourth measuring tube.
 48. The measuring transducer asclaimed in claim 46, wherein: said first and said second oscillationexciters, are interconnected electrically in series, in such a manner,that a combined driver signal excites combined oscillations of saidfirst and said third measuring tubes relative to said second and fourthmeasuring tubes.
 49. The measuring transducer as claimed in claim 48,wherein: said first oscillation exciter is formed by means of apermanent magnet held to said first measuring tube and a cylindricalcoil held to said second measuring tube and permeated by the magneticfield of the permanent magnet.
 50. The measuring transducer as claimedin claim 49, wherein: said second oscillation exciter is formed by meansof a permanent magnet held to said third measuring tube and acylindrical coil held to said fourth measuring tube and permeated by themagnetic field of the permanent magnet.
 51. The measuring transducer asclaimed in claim 50, wherein: both said second oscillation sensor aswell as also said fourth oscillation sensor are held, in each case, tosaid fifth and said sixth coupling elements of the second type,especially in such a manner, that a minimum separation between saidsecond and said fourth oscillation sensors is more than twice as largeas a tube outer diameter of said first measuring tube.
 52. The measuringtransducer as claimed in claim 46, further comprising: a firstplate-shaped stiffening element, which, for tuning resonance frequenciesof bending oscillations of said first measuring tube and said thirdmeasuring tube in a third plane of oscillation essentially perpendicularto at least one of said first and second planes of oscillation, isaffixed to said first measuring tube and to said third measuring tube,and, indeed, in each case, to a segment of said first and said thirdmeasuring tubes lying between said first oscillation exciter and saidfirst flow divider; a second plate-shaped, stiffening element, which,for tuning resonance frequencies of bending oscillations of said secondmeasuring tube and said fourth measuring tube in a fourth plane ofoscillation essentially perpendicular to at least one of said first andsecond planes of oscillation, is affixed to said second measuring tubeand to said fourth measuring tube, and, indeed, in each case, to asegment of said second and said fourth measuring tubes lying betweensaid first oscillation exciter and said first flow divider; a thirdplate-shaped stiffening element, which, for tuning resonance frequenciesof bending oscillations of said first measuring tube and said thirdmeasuring tube in said third plane of oscillation, is affixed to saidfirst measuring tube and to said third measuring tube, and, indeed, ineach case, to a segment of said first and said third measuring tubeslying between said first oscillation exciter and said second flowdivider; and a fourth plate-shaped stiffening element, which, for tuningresonance frequencies of bending oscillations of said second measuringtube and said fourth measuring tube in said fourth plane of oscillation,is affixed to said second measuring tube and to said fourth measuringtube, and, indeed, in each case, to a segment of said second and saidfourth measuring tubes lying between said first oscillation exciter andsaid second flow divider.
 53. The measuring transducer as claimed inclaim 1, wherein: each of said four measuring tubes, especiallymeasuring tubes of equal caliber, is so arranged, that a smallestlateral separation of each of said four measuring tubes, especiallymeasuring tubes of equal length, from a housing side wall of saidtransducer housing is, in each case, greater than zero, especiallygreater than 3 mm and/or greater than twice a respective tube wallthickness; and/or that a smallest lateral separation between twoneighboring measuring tubes is, in each case, greater than 3 mm and/orgreater than the sum of their respective tube wall thicknesses, and/orwherein each of said flow openings is so arranged, that a smallestlateral separation of each of said flow openings from a housing sidewall of said transducer housing is, in each case, greater than zero,especially greater than 3 mm and/or greater than twice a smallest tubewall thickness of said measuring tubes; and/or that a smallest lateralseparation between said flow openings is greater than 3 mm and/orgreater than twice a smallest tube wall thickness of said measuringtubes.
 54. The measuring transducer as claimed in claim 1, furthercomprising: a plurality of annular stiffening elements serving forincreasing a oscillation quality factor of said measuring tubes,wherein: each stiffening element is so placed on exactly one of saidmeasuring tubes, that said respective stiffening element grips aroundsaid respective measuring tube along one of its peripheral lines. 55.The measuring transducer as claimed in claim 54, wherein, on each ofsaid measuring tubes, there are placed at least four annular stiffeningelements; and/or said stiffening elements are so placed in the measuringtransducer, that two adjoining stiffening elements mounted on the samemeasuring tube show, relative to one another, a separation, whichamounts to at least 70% of a tube outer diameter, D_(18a), of saidmeasuring tube, at most, however, 150% of such tube outer diameter,D_(18a).
 56. The measuring transducer as claimed in claim 1, wherein: amass ratio, M₁₁/M₁₈, of an empty mass, M₁₁, of the total measuringtransducer to an empty mass, M₁₈, of said first measuring tube isgreater than 10; each of said two flow dividers shows a mass of morethan 20 kg; an empty mass, M₁₈, of said first measuring tube is greaterthan 20 kg; a material, of which the tube walls of said four measuringtubes are at least partially composed, is titanium and/or zirconiumand/or duplex steel and/or super duplex steel; said transducer housing,said first and said second flow dividers and tube walls of saidmeasuring tubes, are composed, in each case, of steel; said four flowopenings of said first flow divider are so arranged, that imaginaryareal centers of gravity associated with the cross sectional areas, ofsaid flow openings of said first flow divider form the vertices of animaginary square; said cross sectional areas lying in a shared,imaginary, cutting plane of said first flow divider extendingperpendicular to a longitudinal axis of the measuring transducer; saidfour flow openings of said second flow divider are so arranged, thatimaginary areal centers of gravity associated with cross sectionalareas, of said flow openings of said second flow divider form thevertices of an imaginary square, said cross sectional areas lying in ashared, imaginary, cutting plane of said second flow divider extendingperpendicular to a longitudinal axis of the measuring transducer,especially a longitudinal axis parallel to a principal flow axis of themeasuring transducer; and/or a middle segment of said transducer housingis formed by means of a straight tube.
 57. An in-line measuring devicefor measuring a density and/or a mass flow rate of a medium flowing in apipeline, at least at times, which in-line measuring device comprises: ameasuring transducer as claimed in claim 1; as well as a measuringdevice electronics electrically coupled with the measuring transducer,especially also a measuring device electronics mechanically rigidlyconnected with said measuring transducer.
 58. The use of a measuringtransducer according to claim 1 for measuring a density and/or a massflow rate of a medium flowing in a pipeline, at least at times, with amass flow rate of more than 2200 t/h.
 59. The measuring transducer asclaimed in claim 1, wherein: the installed length, L₁₁, of the measuringtransducer amounts to less than 3000 mm.